diff --git a/piker/brokers/deribit/api.py b/piker/brokers/deribit/api.py
index 0450b9eb..5945e634 100644
--- a/piker/brokers/deribit/api.py
+++ b/piker/brokers/deribit/api.py
@@ -123,14 +123,20 @@ def str_to_cb_sym(name: str) -> Symbol:
         type=OPTION,
         strike_price=strike_price,
         option_type=option_type,
-        expiry_date=new_expiry_date)
+        expiry_date=new_expiry_date
+    )
 
 
 def piker_sym_to_cb_sym(name: str) -> Symbol:
-    base, expiry_date, strike_price, option_type = tuple(
+    (
+        base,
+        expiry_date,
+        strike_price,
+        option_type,
+    )= tuple(
         name.upper().split('-'))
 
-    quote = base
+    quote: str = base
 
     if option_type == 'P':
         option_type = PUT 
@@ -145,7 +151,8 @@ def piker_sym_to_cb_sym(name: str) -> Symbol:
         type=OPTION,
         strike_price=strike_price,
         option_type=option_type,
-        expiry_date=expiry_date)
+        expiry_date=expiry_date
+    )
 
 
 def cb_sym_to_deribit_inst(sym: Symbol):
@@ -208,7 +215,10 @@ def get_config() -> dict[str, Any]:
 
 
 class Client:
+    '''
+    Hi-level interface for the jsron-RPC over websocket API.
 
+    '''
     def __init__(
         self,
 
@@ -609,43 +619,59 @@ async def aio_price_feed_relay(
     from_trio: asyncio.Queue,
     to_trio: trio.abc.SendChannel,
 ) -> None:
-    async def _trade(data: dict, receipt_timestamp):
-        to_trio.send_nowait(('trade', {
-            'symbol': cb_sym_to_deribit_inst(
-                str_to_cb_sym(data.symbol)).lower(),
-            'last': data,
-            'broker_ts': time.time(),
-            'data': data.to_dict(),
-            'receipt': receipt_timestamp
-        }))
 
-    async def _l1(data: dict, receipt_timestamp):
-        to_trio.send_nowait(('l1', {
-            'symbol': cb_sym_to_deribit_inst(
-                str_to_cb_sym(data.symbol)).lower(),
-            'ticks': [
-                {
-                    'type': 'bid',
-                    'price': float(data.bid_price),
-                    'size': float(data.bid_size)
-                },
-                {
-                    'type': 'bsize',
-                    'price': float(data.bid_price),
-                    'size': float(data.bid_size)
-                },
-                {
-                    'type': 'ask',
-                    'price': float(data.ask_price),
-                    'size': float(data.ask_size)
-                },
-                {
-                    'type': 'asize',
-                    'price': float(data.ask_price),
-                    'size': float(data.ask_size)
-                }
-            ]
-        }))
+    async def _trade(
+        data: dict,
+        receipt_timestamp: int,
+    ) -> None:
+        '''
+        Send `cryptofeed.FeedHandler` quotes to `piker`-side
+        `trio.Task`.
+
+        '''
+        to_trio.send_nowait((
+            'trade', {
+                'symbol': cb_sym_to_deribit_inst(
+                    str_to_cb_sym(data.symbol)).lower(),
+                'last': data,
+                'broker_ts': time.time(),
+                'data': data.to_dict(),
+                'receipt': receipt_timestamp,
+            },
+        ))
+
+    async def _l1(
+        data: dict,
+        receipt_timestamp: int,
+    ) -> None:
+        to_trio.send_nowait((
+            'l1', {
+               'symbol': cb_sym_to_deribit_inst(
+                    str_to_cb_sym(data.symbol)).lower(),
+                'ticks': [
+                    {
+                        'type': 'bid',
+                        'price': float(data.bid_price),
+                        'size': float(data.bid_size)
+                    },
+                    {
+                        'type': 'bsize',
+                        'price': float(data.bid_price),
+                        'size': float(data.bid_size)
+                    },
+                    {
+                        'type': 'ask',
+                        'price': float(data.ask_price),
+                        'size': float(data.ask_size)
+                    },
+                    {
+                        'type': 'asize',
+                        'price': float(data.ask_price),
+                        'size': float(data.ask_size)
+                    }
+                ]
+            },
+        ))
     sym: Symbol = piker_sym_to_cb_sym(instrument)
     fh.add_feed(
         DERIBIT,