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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 connect(self, protocol=None):
 """Initialize DAP IO pins for JTAG or SWD"""

        # Convert protocol to port enum.
        if protocol is not None:
            port = self.PORT_MAP[protocol]
        else:
            port = DAPAccess.PORT.DEFAULT
        
        try:
            self._link.connect(port)
        except DAPAccess.Error as exc:
            six.raise_from(self._convert_exception(exc), exc)
        
        # Read the current mode and save it.
        actualMode = self._link.get_swj_mode()
        self._protocol = self.PORT_MAP[actualMode]
        
        self._invalidate_cached_registers()