Guard against no time field in some provider quotes

piker/data/_normalize.py

@@ -24,7 +24,10 @@ from typing import AsyncIterator
 
 def iterticks(
     quote: dict,
-    types: tuple[str] = ('trade', 'dark_trade'),
+    types: tuple[str] = (
+        'trade',
+        'dark_trade',
+    ),
     deduplicate_darks: bool = False,
 
 ) -> AsyncIterator:
@@ -47,8 +50,11 @@ def iterticks(
         if deduplicate_darks:
             for tick in ticks:
                 ttype = tick.get('type')
+
+                time = tick.get('time', None)
+                if time:
                     sig = (
-                    tick['time'],
+                        time,
                         tick['price'],
                         tick['size']
                     )