code: def strip_qos_cntrl(self, idx, prot_type):
          
          qos_cntrl, = struct.unpack('H', self._packet[idx:idx + 2])
          qos_cntrl_bits = format(qos_cntrl, '016b')[::-1]
          qos_pri = qos_cntrl & 0x000f
          qos_bit = int(qos_cntrl_bits[5])
          qos_ack = int(qos_cntrl_bits[6:8], 2)
          amsdupresent = 0
          if prot_type == '.11ac':
              amsdupresent = int(qos_cntrl_bits[7])
          return 2, qos_pri, qos_bit, qos_ack, amsdupresent
docs: strip(2 byte) wlan.qos
          :idx: int
          :prot_type: string
              802.11 protocol type(.11ac, .11a, .11n, etc)
          :return: int
              number of processed bytes
          :return: int
              qos priority
          :return: int
              qos bit
          :return: int
              qos acknowledgement
          :return: int
              amsdupresent(aggregated mac service data unit)