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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 _interpolation_escape(self, namespace):
 """ Re-escape interpolation strings. """

        for key, val in namespace.items():
            if '%' in val:
                namespace[key] = self.INTERPOLATION_ESCAPE.sub(lambda match: '%' + match.group(0), val)