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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 get_inner_edges(self):
 """ Returns a list of the internal edges of the tree. """

        inner_edges = [e for e in self._tree.preorder_edge_iter() if e.is_internal()
                       and e.head_node and e.tail_node]
        return inner_edges