'Accept a connection on the bound socket or named pipe of `self`.
Returns a `Connection` object.'

def accept(self):

    if (self._listener is None):
        raise OSError('listener    is    closed')
    c = self._listener.accept()
    if self._authkey:
        deliver_challenge(c, self._authkey)
        answer_challenge(c, self._authkey)
    return c
