ib; return `None` on empty bars frame resp so as to trigger raising `NoData` in the caller

piker/brokers/ib/feed.py

@@ -434,11 +434,8 @@ async def get_bars(
                     # current impl) to detect a cancel case.
                     # timeout=timeout,
                 )
-
-                # not enough bars signal, likely due to venue
-                # operational gaps.
-                # too_little: bool = False
-                if end_dt:
+                # usually either a request during a venue closure
+                # or into a large (weekend) closure gap.
                 if not bars:
                     # no data returned?
                     log.warning(
@@ -447,14 +444,13 @@ async def get_bars(
                         f'end_dt: {end_dt}\n'
                         f'duration: {dt_duration}\n'
                     )
+                    # NOTE: REQUIRED to pass back value..
                     result = None
                     return None
-                        # raise NoData(
-                        #     f'{fqme}\n'
-                        #     f'end_dt:{end_dt}\n'
-                        # )
 
-                    else:
+                # not enough bars signal, likely due to venue
+                # operational gaps.
+                if end_dt:
                     dur_s: float = len(bars) * timeframe
                     bars_dur = Duration(seconds=dur_s)
                     dt_dur_s: float = dt_duration.in_seconds()