def add_requirements(self, metadata_path):
        """Add additional requirements from setup.cfg to file metadata_path"""
        additional = list(self.setupcfg_requirements())
        if not additional: return
        pkg_info = read_pkg_info(metadata_path)
        if 'Provides-Extra' in pkg_info or 'Requires-Dist' in pkg_info:
            warnings.warn('setup.cfg requirements overwrite values from setup.py')
            del pkg_info['Provides-Extra']
            del pkg_info['Requires-Dist']
        for k, v in additional:
            pkg_info[k] = v
        write_pkg_info(metadata_path, pkg_info)
Add additional requirements from setup.cfg to file metadata_path