L2SS-627: Linting regression after merging in master: fix B008 Do not perform...

L2SS-627: Linting regression after merging in master: fix B008 Do not perform function calls in argument defaults.

tangostationcontrol/tangostationcontrol/devices/beam.py

@@ -156,7 +156,7 @@ class Beam(lofar_device):
         else:
             self.HBAT_beam_tracker.stop()
 
-    def _HBAT_delays(self, pointing_direction: numpy.array, timestamp: datetime.datetime = datetime.datetime.now()):
+    def _HBAT_delays(self, pointing_direction: numpy.array, timestamp: datetime.datetime = None):
         """
         Calculate the delays (in seconds) based on the pointing list and the timestamp
         """