code: def set(self, section, option, value=None):
          
          if value:
              value = self._interpolation.before_set(self, section, option,
                                                     value)
          if not section or section == self.default_section:
              sectdict = self._defaults
          else:
              try:
                  sectdict = self._sections[section]
              except KeyError:
                  raise from_none(NoSectionError(section))
          sectdict[self.optionxform(option)] = value
docs: Set an option.