comefrom: <qiyuangong>1323_Maximum_69_Number_1.py
code: def maximum69Number ( num: int) -> int:
      return(str(num).replace('6', '9', 1))
masked: def sample_funcname ( var_0 : int ) -> int :
      return ( str ( var_0 ).replace ( '6' , '9' , 1 ) )
  