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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):
 """ Establish a connection to the master process's UNIX listener socket, constructing a mitogen.master.Router to communicate with the master, and a mitogen.parent.Context to represent it. Depending on the original transport we should emulate, trigger one of the _connect_*() service calls defined above to cause the master process to establish the real connection on our behalf, or return a reference to the existing one. """

        if self.connected:
            return

        self._connect_broker()
        stack = self._build_stack()
        self._connect_stack(stack)