def sh_margins(start=None, end=None, retry_count=3, pause=0.001):
 start = (du.today_last_year() if (start is None) else start)
 end = (du.today() if (end is None) else end)
 if (du.diff_day(start, end) < 0):
  return None
 (start, end) = (start.replace('-', ''), end.replace('-', ''))
 data = pd.DataFrame()
 ct._write_head()
 df = _sh_hz(data, start=start, end=end, retry_count=retry_count, pause=pause)
 return df

def sh_margins ( start = None , end = None , retry_count = 3 , pause = 0.001 ) : start = ( du . today_last_year ( ) if ( start is None ) else start ) end = ( du . today ( ) if ( end is None ) else end ) if ( du . diff_day ( start , end ) < 0 ) : return None ( start , end ) = ( start . replace ( '-' , '' ) , end . replace ( '-' , '' ) ) data = pd . DataFrame ( ) ct . _write_head ( ) df = _sh_hz ( data , start = start , end = end , retry_count = retry_count , pause = pause ) return df
parameters start:string 开始日期 format：yyyy-mm-dd 为空时取去年今日 end:string 结束日期 format：yyyy-mm-dd 为空时取当前日期 retry_count : int .