code: def _unify_values(self, section, vars):
          
          sectiondict = {}
          try:
              sectiondict = self._sections[section]
          except KeyError:
              if section != self.default_section:
                  raise NoSectionError(section)
          # Update with the entry specific variables
          vardict = {}
          if vars:
              for key, value in vars.items():
                  if value is not None:
                      value = str(value)
                  vardict[self.optionxform(key)] = value
          return _ChainMap(vardict, sectiondict, self._defaults)
docs: Create a sequence of lookups with 'vars' taking priority over
          the 'section' which takes priority over the DEFAULTSECT.