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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 summary(self):
 """ Get the entry's summary text """

        if self.get('Summary'):
            return self.get('Summary')

        body, more, is_markdown = self._entry_content
        return TrueCallableProxy(
            self._get_summary,
            body or more) if is_markdown else CallableProxy(None)