def _format_grndt(self, data_c):
monthly_str = '<STR_LIT>'.format(<EOL>data_c.header.metadata['<STR_LIT>'],<EOL>data_c.header.metadata['<STR_LIT>'],<EOL>data_c.header.metadata['<STR_LIT>'],<EOL>'<STR_LIT:U+002C>'.join(['<STR_LIT>' % x for x in data_c.values]))<EOL>return monthly_str<EOL>
Format monthly ground data collection into string for the EPW header.