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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _recv_fc(self, data):
 """Process a received 'Flow Control' frame"""

        if (self.tx_state != ISOTP_WAIT_FC and
                self.tx_state != ISOTP_WAIT_FIRST_FC):
            return 0

        self.tx_timer.cancel()

        if len(data) < 3:
            self.tx_state = ISOTP_IDLE
            self.tx_exception = "CF frame discarded because it was too short"
            self.tx_done.set()
            raise Scapy_Exception(self.tx_exception)

        # get communication parameters only from the first FC frame
        if self.tx_state == ISOTP_WAIT_FIRST_FC:
            self.txfc_bs = six.indexbytes(data, 1)
            self.txfc_stmin = six.indexbytes(data, 2)

        if ((self.txfc_stmin > 0x7F) and
                ((self.txfc_stmin < 0xF1) or (self.txfc_stmin > 0xF9))):
            self.txfc_stmin = 0x7F

        if six.indexbytes(data, 2) <= 127:
            tx_gap = six.indexbytes(data, 2) / 1000.0
        elif 0xf1 <= six.indexbytes(data, 2) <= 0xf9:
            tx_gap = (six.indexbytes(data, 2) & 0x0f) / 10000.0
        else:
            tx_gap = 0
        self.tx_gap = tx_gap

        self.tx_state = ISOTP_WAIT_FC

        isotp_fc = six.indexbytes(data, 0) & 0x0f

        if isotp_fc == ISOTP_FC_CTS:
            self.tx_bs = 0
            self.tx_state = ISOTP_SENDING
            # start cyclic timer for sending CF frame
            self.tx_timer.set_timeout(self.tx_gap, self._tx_timer_handler)
        elif isotp_fc == ISOTP_FC_WT:
            # start timer to wait for next FC frame
            self.tx_state = ISOTP_WAIT_FC
            self.tx_timer.set_timeout(self.fc_timeout, self._tx_timer_handler)
        elif isotp_fc == ISOTP_FC_OVFLW:
            # overflow in receiver side
            self.tx_state = ISOTP_IDLE
            self.tx_exception = "Overflow happened at the receiver side"
            self.tx_done.set()
            raise Scapy_Exception(self.tx_exception)
        else:
            self.tx_state = ISOTP_IDLE
            self.tx_exception = "Unknown FC frame type"
            self.tx_done.set()
            raise Scapy_Exception(self.tx_exception)

        return 0