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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 with_outer_namespace(self, outer_namespace):
 """Return a new EvalEnvironment with an extra namespace added. This namespace will be used only for variables that are not found in any existing namespace, i.e., it is "outside" them all."""

        return self.__class__(self._namespaces + [outer_namespace],
                              self.flags)