code: def strip_bitmap_str(payload):
          
          bitmap = struct.unpack('BBBBBBBB', payload)
          bitmap_str = ''
          for elem in bitmap:
              bitmap_str += format(elem, '08b')[::-1]
          return bitmap_str
docs: strip(8 byte) wlan.ba.bm
          :payload: ctypes.structure
          :return: str
              bitmap