L2SS-769: Added comment describing extra parameter that disappears in use and inheritance

tangostationcontrol/tangostationcontrol/devices/beam_device.py

@@ -157,6 +157,8 @@ class beam_device(lofar_device):
         # generic delay calculator to ask about validity of settings
         self.generic_delay_calculator = delay_calculator([0, 0, 0])
 
+    # Derived  classes will override this with a non-parameterised
+    # version that lofar_device will call.
     @log_exceptions()
     def configure_for_initialise(self, num_pointings):
         super().configure_for_initialise()