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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 find_source(self, source):
 """ Given a source, find it. source can be a url or an index name. """

        if not is_valid_url(source):
            try:
                source = self.get_source(name=source)
            except SourceNotFound:
                source = self.get_source(url=source)
        else:
            source = self.get_source(url=source)
        return source