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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 link(self, to):
 """Link to another process. The ``link`` operation is not guaranteed to succeed. If it does, when the other process terminates, the ``exited`` method will be called with its pid. Returns immediately. :param to: The pid of the process to send a message. :type to: :class:`PID` :raises: Will raise a ``Process.UnboundProcess`` exception if the process is not bound to a context. :return: Nothing """

    self._assert_bound()
    self._context.link(self.pid, to)