code: def set(self, section, option, value=None):
          
          try:
              section = self.__getitem__(section)
          except KeyError:
              raise NoSectionError(section) from None
          option = self.optionxform(option)
          if option in section:
              section[option].value = value
          else:
              section[option] = value
          return self
docs: Set an option.
  
          Args:
              section (str): section name
              option (str): option name
              value (str): value, default None