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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 raise_for_redefined_namespace(self, line: str, position: int, namespace: str) -> None: """Raise an exception if a namespace is already defined. :raises: RedefinedNamespaceError """

        if self.disallow_redefinition and self.has_namespace(namespace):
            raise RedefinedNamespaceError(self.get_line_number(), line, position, namespace)