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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 _pop_input_state(self, node):
 """ Get the input abstract state for this node, and remove it from the state map. :param node: The node in graph. :return: A merged state, or None if there is no input state for this node available. """


        if node in self._state_map:
            return self._state_map.pop(node)
        return None