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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 namespaces( self, name=None, function=None, recursive=None, allow_empty=None):
 """ Returns a set of namespace declarations that match a defined criteria. """


        return (
            self._find_multiple(
                scopedef.scopedef_t._impl_matchers[namespace_t.namespace],
                name=name,
                function=function,
                recursive=recursive,
                allow_empty=allow_empty)
        )