code: def has_option(self, section, option):
          
          if not section or section == self.default_section:
              option = self.optionxform(option)
              return option in self._defaults
          elif section not in self._sections:
              return False
          else:
              option = self.optionxform(option)
              return (option in self._sections[section]
                      or option in self._defaults)
docs: Check for the existence of a given option in a given section.
          If the specified `section' is None or an empty string, DEFAULT is
          assumed. If the specified `section' does not exist, returns False.