add get_mkt_pairs method

piker/brokers/deribit/api.py

@@ -328,6 +328,13 @@ class Client:
                 tx_tick=tx_tick)
         return assets 
 
+    async def get_mkt_pairs(self) -> dict[str, Pair]:
+        flat: dict[str, Pair] = {}
+        for key in self._pairs:
+            item = self._pairs.get(key)
+            flat[item.bs_fqme] = item
+
+        return flat
 
     async def submit_limit(
         self,