code: def do_glob_math(self, cont):
          
          # TODO that's a lie!  this should be in the parser for most cases.
          if not isinstance(cont, six.string_types):
              warn(FutureWarning(
                  "do_glob_math was passed a non-string {0!r} "
                  "-- this will no longer be supported in pyScss 2.0"
                  .format(cont)
              ))
              cont = six.text_type(cont)
          if '#{' not in cont:
              return cont
          cont = _expr_glob_re.sub(self._pound_substitute, cont)
          return cont
docs: Performs #{}-interpolation.  The result is always treated as a fixed
          syntactic unit and will not be re-evaluated.