Merge pull request #214 from iamzoltan/kraken_orders

Phil MacKraken

config/brokers.toml

@@ -8,8 +8,8 @@ expires_at = 1616095326.355846
 
 [kraken]
 key_descr = "api_0"
-public_key = ""
+api_key = ""
-private_key = ""
+secret = ""
 
 [ib]
 host = "127.0.0.1"

piker/brokers/kraken.py

@@ -14,13 +14,13 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-"""
+'''
 Kraken backend.
 
-"""
+'''
 from contextlib import asynccontextmanager
 from dataclasses import asdict, field
-from typing import List, Dict, Any, Tuple, Optional
+from typing import Dict, List, Tuple, Any, Optional, AsyncIterator
 import time
 
 from trio_typing import TaskStatus
@@ -33,12 +33,25 @@ import tractor
 from pydantic.dataclasses import dataclass
 from pydantic import BaseModel
 import wsproto
+from itertools import count
+import urllib.parse
+import hashlib
+import hmac
+import base64
 
+from .. import config
 from .._cacheables import open_cached_client
 from ._util import resproc, SymbolNotFound, BrokerError
 from ..log import get_logger, get_console_log
 from ..data import ShmArray
-from ..data._web_bs import open_autorecon_ws
+from ..data._web_bs import open_autorecon_ws, NoBsWs
+from ..clearing._paper_engine import PaperBoi
+from ..clearing._messages import (
+    BrokerdPosition, BrokerdOrder, BrokerdStatus,
+    BrokerdOrderAck, BrokerdError, BrokerdCancel,
+    BrokerdFill,
+)
+
 
 log = get_logger(__name__)
 
@@ -106,13 +119,27 @@ class Pair(BaseModel):
     ordermin: float  # minimum order volume for pair
 
 
+class Trade(BaseModel):
+    '''
+    Trade class that helps parse and validate ownTrades stream
+
+    '''
+    reqid: str # kraken order transaction id
+    action: str # buy or sell
+    price: str # price of asset
+    size: str # vol of asset
+    broker_time: str # e.g GTC, GTD
+
+
 @dataclass
 class OHLC:
-    """Description of the flattened OHLC quote format.
+    '''
+    Description of the flattened OHLC quote format.
 
     For schema details see:
         https://docs.kraken.com/websockets/#message-ohlc
-    """
+
+    '''
     chan_id: int  # internal kraken id
     chan_name: str  # eg. ohlc-1  (name-interval)
     pair: str  # fx pair
@@ -129,9 +156,52 @@ class OHLC:
     ticks: List[Any] = field(default_factory=list)
 
 
+def get_config() -> dict[str, Any]:
+
+    conf, path = config.load()
+
+    section = conf.get('kraken')
+
+    if section is None:
+        log.warning(f'No config section found for kraken in {path}')
+        return {}
+
+    return section
+
+
+def get_kraken_signature(
+    urlpath: str,
+    data: Dict[str, Any],
+    secret: str
+) -> str:
+    postdata = urllib.parse.urlencode(data)
+    encoded = (str(data['nonce']) + postdata).encode()
+    message = urlpath.encode() + hashlib.sha256(encoded).digest()
+
+    mac = hmac.new(base64.b64decode(secret), message, hashlib.sha512)
+    sigdigest = base64.b64encode(mac.digest())
+    return sigdigest.decode()
+
+
+class InvalidKey(ValueError):
+    '''
+    EAPI:Invalid key
+    This error is returned when the API key used for the call is
+    either expired or disabled, please review the API key in your
+    Settings -> API tab of account management or generate a new one
+    and update your application.
+
+    '''
+
+
 class Client:
 
-    def __init__(self) -> None:
+    def __init__(
+        self,
+        name: str = '',
+        api_key: str = '',
+        secret: str = ''
+    ) -> None:
         self._sesh = asks.Session(connections=4)
         self._sesh.base_location = _url
         self._sesh.headers.update({
@@ -139,6 +209,9 @@ class Client:
                 'krakenex/2.1.0 (+https://github.com/veox/python3-krakenex)'
         })
         self._pairs: list[str] = []
+        self._name = name
+        self._api_key = api_key
+        self._secret = secret
 
     @property
     def pairs(self) -> Dict[str, Any]:
@@ -162,6 +235,108 @@ class Client:
         )
         return resproc(resp, log)
 
+    async def _private(
+        self,
+        method: str,
+        data: dict,
+        uri_path: str
+    ) -> Dict[str, Any]:
+        headers = {
+            'Content-Type': 
+                'application/x-www-form-urlencoded',
+            'API-Key':
+                self._api_key,
+            'API-Sign':
+                get_kraken_signature(uri_path, data, self._secret)
+        }
+        resp = await self._sesh.post(
+            path=f'/private/{method}',
+            data=data,
+            headers=headers,
+            timeout=float('inf')
+        )
+        return resproc(resp, log)
+
+    async def endpoint(
+        self,
+        method: str,
+        data: Dict[str, Any]
+    ) -> Dict[str, Any]:
+        uri_path = f'/0/private/{method}'
+        data['nonce'] = str(int(1000*time.time()))
+        return await self._private(method, data, uri_path)
+
+    async def get_trades(
+        self,
+        data: Dict[str, Any] = {}
+    ) -> Dict[str, Any]:
+        data['ofs'] = 0
+        # Grab all trade history
+        # https://docs.kraken.com/rest/#operation/getTradeHistory
+        # Kraken uses 'ofs' to refer to the offset
+        while True:
+            resp = await self.endpoint('TradesHistory', data)
+            # grab the first 50 trades
+            if data['ofs'] == 0:
+                trades = resp['result']['trades']
+            # load the next 50 trades using dict constructor
+            # for speed
+            elif data['ofs'] == 50:
+                trades = dict(trades, **resp['result']['trades'])
+            # catch the end of the trades
+            elif resp['result']['trades'] == {}:
+                count = resp['result']['count']
+                break
+            # update existing dict if num trades exceeds 100
+            else: 
+                trades.update(resp['result']['trades'])
+            # increment the offset counter
+            data['ofs'] += 50
+            # To avoid exceeding API rate limit in case of a lot of trades
+            await trio.sleep(1)
+
+        # make sure you grabbed all the trades
+        assert count == len(trades.values())
+
+        return trades
+
+    async def submit_limit(
+        self,
+        oid: str,
+        symbol: str,
+        price: float,
+        action: str,
+        size: float,
+        reqid: int = None,
+    ) -> int:
+        '''
+        Place an order and return integer request id provided by client.
+
+        '''
+        # Build order data for kraken api
+        data = {
+            "userref": reqid,
+            "ordertype": "limit",
+            "type": action,
+            "volume": str(size),
+            "pair": symbol,
+            "price": str(price),
+            # set to True test AddOrder call without a real submission
+            "validate": False
+        }
+        return await self.endpoint('AddOrder', data)
+
+    async def submit_cancel(
+        self,
+        reqid: str,
+    ) -> None:
+        '''
+        Send cancel request for order id ``reqid``.
+
+        '''
+        # txid is a transaction id given by kraken
+        return await self.endpoint('CancelOrder', {"txid": reqid})
+
     async def symbol_info(
         self,
         pair: Optional[str] = None,
@@ -271,8 +446,18 @@ class Client:
             raise SymbolNotFound(json['error'][0] + f': {symbol}')
 
 
+
 @asynccontextmanager
 async def get_client() -> Client:
+
+    section = get_config()
+    if section: 
+        client = Client(
+            name=section['key_descr'],
+            api_key=section['api_key'],
+            secret=section['secret']
+        )
+    else:
         client = Client()
 
     # at startup, load all symbols locally for fast search
@@ -281,8 +466,347 @@ async def get_client() -> Client:
     yield client
 
 
-async def stream_messages(ws):
+def pack_positions(
+    acc: str,
+    trades: dict
+) -> list[Any]:
+    positions: dict[str, float] = {}
+    vols: dict[str, float] = {}
+    costs: dict[str, float] = {}
+    position_msgs: list[Any] = []
 
+    for trade in trades.values():
+        sign = -1 if trade['type'] == 'sell' else 1
+        pair = trade['pair']
+        vol = float(trade['vol'])
+        vols[pair] = vols.get(pair, 0) + sign * vol
+        costs[pair] = costs.get(pair, 0) + sign * float(trade['cost'])
+        positions[pair] = costs[pair] / vols[pair] if vols[pair] else 0
+
+    for ticker, pos in positions.items():
+        vol = float(vols[ticker])
+        if not vol:
+            continue
+        norm_sym = normalize_symbol(ticker)
+        msg = BrokerdPosition(
+            broker='kraken',
+            account=acc,
+            symbol=norm_sym,
+            currency=norm_sym[-3:],
+            size=vol,
+            avg_price=float(pos),
+        )
+        position_msgs.append(msg.dict())
+
+    return position_msgs
+
+
+def normalize_symbol(
+    ticker: str
+) -> str:
+    # This is to convert symbol names from what kraken
+    # uses to the traditional 3x3 pair symbol syntax
+    symlen = len(ticker)
+    if symlen == 6:
+        return ticker.lower()
+    else:
+        for sym in ['XXBT', 'XXMR', 'ZEUR']:
+            if sym in ticker:
+                ticker = ticker.replace(sym, sym[1:])
+        return ticker.lower()
+
+
+def make_auth_sub(data: Dict[str, Any]) -> Dict[str, str]:
+    '''
+    Create a request subscription packet dict.
+
+    ## TODO: point to the auth urls
+    https://docs.kraken.com/websockets/#message-subscribe
+
+    '''
+    # eg. specific logic for this in kraken's sync client:
+    # https://github.com/krakenfx/kraken-wsclient-py/blob/master/kraken_wsclient_py/kraken_wsclient_py.py#L188
+    return {
+        'event': 'subscribe',
+        'subscription': data,
+    }
+
+
+async def handle_order_requests(
+
+        client: Client,
+        ems_order_stream: tractor.MsgStream,
+
+) -> None:
+
+    request_msg: dict
+    order: BrokerdOrder
+    userref_counter = count()
+    async for request_msg in ems_order_stream:
+        log.info(f'Received order request {request_msg}')
+
+        action = request_msg['action']
+
+        if action in {'buy', 'sell'}:
+
+            account = request_msg['account']
+            if account != 'kraken.spot':
+                log.error(
+                    'This is a kraken account, \
+                    only a `kraken.spot` selection is valid'
+                )
+                await ems_order_stream.send(BrokerdError(
+                    oid=request_msg['oid'],
+                    symbol=request_msg['symbol'],
+                    reason=f'Kraken only, No account found: `{account}` ?',
+                ).dict())
+                continue
+
+            # validate
+            temp_id = next(userref_counter)
+            order = BrokerdOrder(**request_msg)
+            
+            # call our client api to submit the order
+            resp = await client.submit_limit(
+                oid=order.oid,
+                symbol=order.symbol,
+                price=order.price,
+                action=order.action,
+                size=order.size,
+                reqid=temp_id,
+            )
+
+            err = resp['error']
+            if err:
+                log.error(f'Failed to submit order')
+                await ems_order_stream.send(
+                    BrokerdError(
+                        oid=order.oid,
+                        reqid=temp_id,
+                        symbol=order.symbol,
+                        reason="Failed order submission",
+                        broker_details=resp
+                    ).dict()
+                )
+            else:
+                # TODO: handle multiple cancels
+                #       txid is an array of strings
+                reqid = resp['result']['txid'][0]
+                # deliver ack that order has been submitted to broker routing
+                await ems_order_stream.send(
+                    BrokerdOrderAck(
+
+                        # ems order request id
+                        oid=order.oid,
+
+                        # broker specific request id
+                        reqid=reqid,
+
+                        # account the made the order
+                        account=order.account
+
+                    ).dict()
+                )
+
+        elif action == 'cancel':
+            msg = BrokerdCancel(**request_msg)
+
+            # Send order cancellation to kraken
+            resp = await client.submit_cancel(
+                reqid=msg.reqid
+            )
+
+            try:
+                # Check to make sure there was no error returned by
+                # the kraken endpoint. Assert one order was cancelled
+                assert resp['error'] == []
+                assert resp['result']['count'] == 1
+
+                # TODO: Change this code using .get
+                try:
+                    pending = resp['result']['pending']
+                # Check to make sure the cancellation is NOT pending,
+                # then send the confirmation to the ems order stream
+                except KeyError:
+                    await ems_order_stream.send(
+                        BrokerdStatus(
+                            reqid=msg.reqid,
+                            account=msg.account,
+                            time_ns=time.time_ns(),
+                            status='cancelled',
+                            reason='Order cancelled',
+                            broker_details={'name': 'kraken'}
+                        ).dict()
+                    )
+            except AssertionError:
+                log.error(f'Order cancel was not successful')
+                await ems_order_stream.send(
+                    BrokerdError(
+                        oid=order.oid,
+                        reqid=temp_id,
+                        symbol=order.symbol,
+                        reason="Failed order cancel",
+                        broker_details=resp
+                    ).dict()
+                )
+
+        else:
+            log.error(f'Unknown order command: {request_msg}')
+
+
+@tractor.context
+async def trades_dialogue(
+    ctx: tractor.Context,
+    loglevel: str = None,
+) -> AsyncIterator[Dict[str, Any]]:
+
+    # XXX: required to propagate ``tractor`` loglevel to piker logging
+    get_console_log(loglevel or tractor.current_actor().loglevel)
+
+    @asynccontextmanager
+    async def subscribe(ws: wsproto.WSConnection, token: str):
+        # XXX: setup subs
+        # https://docs.kraken.com/websockets/#message-subscribe
+        # specific logic for this in kraken's shitty sync client:
+        # https://github.com/krakenfx/kraken-wsclient-py/blob/master/kraken_wsclient_py/kraken_wsclient_py.py#L188
+        trades_sub = make_auth_sub(
+            {'name': 'ownTrades', 'token': token}
+        )
+
+        # TODO: we want to eventually allow unsubs which should
+        # be completely fine to request from a separate task
+        # since internally the ws methods appear to be FIFO
+        # locked.
+        await ws.send_msg(trades_sub)
+
+        yield
+
+        # unsub from all pairs on teardown
+        await ws.send_msg({
+            'event': 'unsubscribe',
+            'subscription': ['ownTrades'],
+        })
+
+        # XXX: do we need to ack the unsub?
+        # await ws.recv_msg()
+
+    # Authenticated block
+    async with get_client() as client:
+        if not client._api_key:
+            log.error('Missing Kraken API key: Trades WS connection failed')
+            await ctx.started(({}, {'paper',}))
+
+            async with (
+                ctx.open_stream() as ems_stream,
+                trio.open_nursery() as n,
+            ):
+
+                client = PaperBoi(
+                    'kraken',
+                    ems_stream,
+                    _buys={},
+                    _sells={},
+
+                    _reqids={},
+
+                    # TODO: load paper positions from ``positions.toml``
+                    _positions={},
+                )
+
+                ## TODO: maybe add multiple accounts
+                n.start_soon(handle_order_requests, client, ems_stream)
+
+        acc_name = 'kraken.' + client._name
+        trades = await client.get_trades()
+
+        position_msgs = pack_positions(acc_name, trades)
+
+        await ctx.started((position_msgs, (acc_name,)))
+
+        # Get websocket token for authenticated data stream
+        # Assert that a token was actually received 
+        resp = await client.endpoint('GetWebSocketsToken', {})
+        assert resp['error'] == []
+        token = resp['result']['token']
+
+        async with (
+            ctx.open_stream() as ems_stream,
+            trio.open_nursery() as n,
+        ):
+            ## TODO: maybe add multiple accounts
+            n.start_soon(handle_order_requests, client, ems_stream)
+
+            # Process trades msg stream of ws
+            async with open_autorecon_ws(
+                'wss://ws-auth.kraken.com/',
+                fixture=subscribe,
+                token=token,
+            ) as ws:
+                async for msg in process_trade_msgs(ws):
+                    for trade in msg:
+                        # check the type of packaged message
+                        assert type(trade) == Trade
+                        # prepare and send a status update for line update
+                        trade_msg = BrokerdStatus(
+                            reqid=trade.reqid,
+                            time_ns=time.time_ns(),
+
+                            account='kraken.spot',
+                            status='executed',
+                            filled=float(trade.size),
+                            reason='Order filled by kraken',
+                            # remaining='' # TODO: not sure what to do here.
+                            broker_details={
+                                'name': 'kraken',
+                                'broker_time': trade.broker_time
+                            }
+                        )
+                        
+                        await ems_stream.send(trade_msg.dict())
+
+                        filled_msg = BrokerdStatus(
+                            reqid=trade.reqid,
+                            time_ns=time.time_ns(),
+
+                            account='kraken.spot',
+                            status='filled',
+                            filled=float(trade.size),
+                            reason='Order filled by kraken',
+                            # remaining='' # TODO: not sure what to do here.
+                            broker_details={
+                                'name': 'kraken',
+                                'broker_time': trade.broker_time
+                            }
+                        )
+                        
+                        await ems_stream.send(filled_msg.dict())
+
+                        # send a fill msg for gui update
+                        fill_msg = BrokerdFill(
+                            reqid=trade.reqid,
+                            time_ns=time.time_ns(),
+
+                            action=trade.action,
+                            size=float(trade.size),
+                            price=float(trade.price),
+                            # TODO: maybe capture more msg data i.e fees?
+                            broker_details={'name': 'kraken'},
+                            broker_time=float(trade.broker_time)
+                        )
+                        
+                        await ems_stream.send(fill_msg.dict())
+
+
+async def stream_messages(
+    ws: NoBsWs,
+):
+    '''
+    Message stream parser and heartbeat handler.
+
+    Deliver ws subscription messages as well as handle heartbeat logic
+    though a single async generator.
+
+    '''
     too_slow_count = last_hb = 0
 
     while True:
@@ -320,6 +844,18 @@ async def stream_messages(ws):
             if err:
                 raise BrokerError(err)
         else:
+            yield msg
+
+
+async def process_data_feed_msgs(
+    ws: NoBsWs,
+):
+    '''
+    Parse and pack data feed messages.
+
+    '''
+    async for msg in stream_messages(ws):
+
         chan_id, *payload_array, chan_name, pair = msg
 
         if 'ohlc' in chan_name:
@@ -349,10 +885,54 @@ async def stream_messages(ws):
 
         else:
             print(f'UNHANDLED MSG: {msg}')
+            yield msg
+
+
+async def process_trade_msgs(
+    ws: NoBsWs,
+):
+    '''
+    Parse and pack data feed messages.
+
+    '''
+    sequence_counter = 0
+    async for msg in stream_messages(ws):
+
+        try:
+            # check that we are on the ownTrades stream and that msgs are 
+            # arriving in sequence with kraken
+            # For clarification the kraken ws api docs for this stream: 
+            #   https://docs.kraken.com/websockets/#message-ownTrades
+            assert msg[1] == 'ownTrades'
+            assert msg[2]['sequence'] > sequence_counter
+            sequence_counter += 1
+            raw_msgs = msg[0]
+            trade_msgs = []
+
+            # Check that we are only processing new trades
+            if msg[2]['sequence'] != 1:
+                # check if its a new order or an update msg
+                for trade_msg in raw_msgs:
+                    trade = list(trade_msg.values())[0]
+                    order_msg = Trade(
+                        reqid=trade['ordertxid'],
+                        action=trade['type'],
+                        price=trade['price'],
+                        size=trade['vol'],
+                        broker_time=trade['time']
+                    )
+                    trade_msgs.append(order_msg)
+
+            yield trade_msgs
+
+        except AssertionError:
+            print(f'UNHANDLED MSG: {msg}')
+            yield msg
 
 
 def normalize(
     ohlc: OHLC,
+
 ) -> dict:
     quote = asdict(ohlc)
     quote['broker_ts'] = quote['time']
@@ -371,11 +951,12 @@ def normalize(
 
 
 def make_sub(pairs: List[str], data: Dict[str, Any]) -> Dict[str, str]:
-    """Create a request subscription packet dict.
+    '''
+    Create a request subscription packet dict.
 
     https://docs.kraken.com/websockets/#message-subscribe
 
-    """
+    '''
     # eg. specific logic for this in kraken's sync client:
     # https://github.com/krakenfx/kraken-wsclient-py/blob/master/kraken_wsclient_py/kraken_wsclient_py.py#L188
     return {
@@ -393,8 +974,9 @@ async def backfill_bars(
     task_status: TaskStatus[trio.CancelScope] = trio.TASK_STATUS_IGNORED,
 
 ) -> None:
-    """Fill historical bars into shared mem / storage afap.
+    '''
-    """
+    Fill historical bars into shared mem / storage afap.
+    '''
     with trio.CancelScope() as cs:
         async with open_cached_client('kraken') as client:
             bars = await client.bars(symbol=sym)
@@ -416,10 +998,12 @@ async def stream_quotes(
     task_status: TaskStatus[Tuple[Dict, Dict]] = trio.TASK_STATUS_IGNORED,
 
 ) -> None:
-    """Subscribe for ohlc stream of quotes for ``pairs``.
+    '''
+    Subscribe for ohlc stream of quotes for ``pairs``.
 
     ``pairs`` must be formatted <crypto_symbol>/<fiat_symbol>.
-    """
+
+    '''
     # XXX: required to propagate ``tractor`` loglevel to piker logging
     get_console_log(loglevel or tractor.current_actor().loglevel)
 
@@ -491,15 +1075,16 @@ async def stream_quotes(
             # XXX: do we need to ack the unsub?
             # await ws.recv_msg()
 
-        # see the tips on reonnection logic:
+        # see the tips on reconnection logic:
         # https://support.kraken.com/hc/en-us/articles/360044504011-WebSocket-API-unexpected-disconnections-from-market-data-feeds
+        ws: NoBsWs
         async with open_autorecon_ws(
             'wss://ws.kraken.com/',
             fixture=subscribe,
         ) as ws:
 
             # pull a first quote and deliver
-            msg_gen = stream_messages(ws)
+            msg_gen = process_data_feed_msgs(ws)
 
             # TODO: use ``anext()`` when it lands in 3.10!
             typ, ohlc_last = await msg_gen.__anext__()
@@ -558,6 +1143,7 @@ async def stream_quotes(
 @tractor.context
 async def open_symbol_search(
     ctx: tractor.Context,
+
 ) -> Client:
     async with open_cached_client('kraken') as client:
 

piker/clearing/_ems.py

@@ -493,7 +493,8 @@ async def open_brokerd_trades_dialogue(
         finally:
             # parent context must have been closed
             # remove from cache so next client will respawn if needed
-            _router.relays.pop(broker)
+            ## TODO: Maybe add a warning
+            _router.relays.pop(broker, None)
 
 
 @tractor.context

piker/clearing/_paper_engine.py

@@ -389,7 +389,7 @@ async def handle_order_requests(
             account = request_msg['account']
             if account != 'paper':
                 log.error(
-                    'On a paper account, only a `paper` selection is valid'
+                    'This is a paper account, only a `paper` selection is valid'
                 )
                 await ems_order_stream.send(BrokerdError(
                     oid=request_msg['oid'],
@@ -463,7 +463,8 @@ async def trades_dialogue(
     ):
         # TODO: load paper positions per broker from .toml config file
         # and pass as symbol to position data mapping: ``dict[str, dict]``
-        await ctx.started(({}, ['paper']))
+        # await ctx.started(all_positions)
+        await ctx.started(({}, {'paper',}))
 
         async with (
             ctx.open_stream() as ems_stream,

piker/data/_web_bs.py

@@ -53,11 +53,13 @@ class NoBsWs:
     def __init__(
         self,
         url: str,
+        token: str,
         stack: AsyncExitStack,
         fixture: Callable,
         serializer: ModuleType = json,
     ):
         self.url = url
+        self.token = token
         self.fixture = fixture
         self._stack = stack
         self._ws: 'WebSocketConnection' = None  # noqa
@@ -81,9 +83,15 @@ class NoBsWs:
                     trio_websocket.open_websocket_url(self.url)
                 )
                 # rerun user code fixture
+                if self.token == '':
                     ret = await self._stack.enter_async_context(
                         self.fixture(self)
                     )
+                else:
+                    ret = await self._stack.enter_async_context(
+                        self.fixture(self, self.token)
+                    )
+
                 assert ret is None
 
                 log.info(f'Connection success: {self.url}')
@@ -127,12 +135,14 @@ async def open_autorecon_ws(
 
     # TODO: proper type annot smh
     fixture: Callable,
+    # used for authenticated websockets
+    token: str = '',
 ) -> AsyncGenerator[tuple[...],  NoBsWs]:
     """Apparently we can QoS for all sorts of reasons..so catch em.
 
     """
     async with AsyncExitStack() as stack:
-        ws = NoBsWs(url, stack, fixture=fixture)
+        ws = NoBsWs(url, token, stack, fixture=fixture)
         await ws._connect()
 
         try: