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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 _merge_state_from_predecessors(self, node):
 """ Get abstract states for all predecessors of the node, merge them, and return the merged state. :param node: The node in graph. :return: A merged state, or None if no predecessor is available. """


        preds = self._graph_visitor.predecessors(node)

        states = [ self._state_map[n] for n in preds if n in self._state_map ]

        if not states:
            return None

        return reduce(lambda s0, s1: self._merge_states(node, s0, s1), states[1:], states[0])