def make_null_event_date_events(all_sids, timestamp):
 return pd.DataFrame({'sid': all_sids, 'timestamp': timestamp, 'event_date': pd.Timestamp('NaT'), 'float': (-9999.0), 'int': (-9999), 'datetime': pd.Timestamp('1980'), 'string': 'should be ignored'})

def make_null_event_date_events ( all_sids , timestamp ) : return pd . DataFrame ( { 'sid' : all_sids , 'timestamp' : timestamp , 'event_date' : pd . Timestamp ( 'NaT' ) , 'float' : ( - 9999.0 ) , 'int' : ( - 9999 ) , 'datetime' : pd . Timestamp ( '1980' ) , 'string' : 'should be ignored' } )
make an event with a null event_date for all sids .