comefrom: <doocs>1323.Maximum 69 Number_1.py
code: def maximum69Number( num: int) -> int:
      return int(str(num).replace("6", "9", 1))
masked: def sample_funcname ( var_0 : int ) -> int :
      return int ( str ( var_0 ).replace ( "6" , "9" , 1 ) )
  