def _dep_map(self):
        """
        A map of extra to its list of (direct) requirements
        for this distribution, including the null extra.
        """
        try:
            return self.__dep_map
        except AttributeError:
            self.__dep_map = self._filter_extras(self._build_dep_map())
        return self.__dep_map

        A map of extra to its list of (direct) requirements
        for this distribution, including the null extra.
        
product/gradle-plugin/src/main/python/pkg_resources/__init__.py