code: def millis_offset_between_epochs(reference_epoch, target_epoch):
      
      assert isinstance(reference_epoch, int)
      assert isinstance(target_epoch, int)
      return (target_epoch - reference_epoch)*1000
docs: Calculates the signed milliseconds delta between the reference unix epoch and the provided target unix epoch
      :param reference_epoch: the unix epoch that the millis offset has to be calculated with respect to
      :type reference_epoch: int
      :param target_epoch: the unix epoch for which the millis offset has to be calculated
      :type target_epoch: int
      :return: int