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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 _preprocess_edges_for_pydot(edges_with_data):
 """throw away all edge attributes, except for 'label'"""

    for (source, target, attrs) in edges_with_data:
        if 'label' in attrs:
            yield (quote_for_pydot(source), quote_for_pydot(target),
                   {'label': quote_for_pydot(attrs['label'])})
        else:
            yield (quote_for_pydot(source), quote_for_pydot(target), {})