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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_index(self, field_name, catalog):
 """Returns the index of the catalog for the given field_name, if any """

        index = catalog.Indexes.get(field_name, None)
        if not index and field_name == "Title":
            # Legacy
            return self.get_index("sortable_title", catalog)
        return index