def TSKVsPartGetStartSector(tsk_vs_part):
    """Retrieves the start sector of a TSK volume system part object.

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

  Returns:
    int: start sector or None.
  """
    return getattr(tsk_vs_part, 'start', None)
