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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 _add_edus_to_tree(parented_tree, edus):
 """replace EDU indices with the text of the EDUs in a parented tree. Parameters parented_tree : nltk.ParentedTree a parented tree that only contains EDU indices as leaves edus : list(list(unicode)) a list of EDUs, where each EDU is represented as a list of tokens """

    for i, child in enumerate(parented_tree):
        if isinstance(child, nltk.Tree):
            _add_edus_to_tree(child, edus)
        else:
            edu_index = int(child)
            edu_tokens = edus[edu_index]
            parented_tree[i] = u" ".join(edu_tokens)