def update_mongo_compound_variants(self, bulk):
requests = []<EOL>for var_id in bulk:<EOL><INDENT>var_obj = bulk[var_id]<EOL>if not var_obj.get('<STR_LIT>'):<EOL><INDENT>continue<EOL><DEDENT>operation = pymongo.UpdateOne(<EOL>{'<STR_LIT>': var_obj['<STR_LIT>']},<EOL>{<EOL>'<STR_LIT>': {<EOL>'<STR_LIT>': var_obj['<STR_LIT>']<EOL>}<EOL>})<EOL>requests.append(operation)<EOL><DEDENT>if not requests:<EOL><INDENT>return<EOL><DEDENT>try:<EOL><INDENT>self.variant_collection.bulk_write(requests, ordered=False)<EOL><DEDENT>except BulkWriteError as err:<EOL><INDENT>LOG.warning("<STR_LIT>")<EOL>raise err<EOL><DEDENT>
Update the compound information for a bulk of variants in the database

            Args:
                bulk(dict): {'_id': scout.models.Variant}