def TSKVsPartGetNumberOfSectors(tsk_vs_part):
    """Retrieves the number of sectors of a TSK volume system part object.

  Args:
    tsk_vs_part (pytsk3.TSK_VS_PART_INFO): TSK volume system part information.

  Returns:
    int: number of sectors or None.
  """
    return getattr(tsk_vs_part, 'len', None)
