code: def parse_vars_and_interpolations(self, string):
          
          # Shortcut: if there are no #s or $s in the string in the first place,
          # it must not have anything of interest.
          if '#' not in string and '$' not in string:
              return Literal(String.unquoted(string))
          return self.parse_expression(
              string, 'goal_interpolated_literal_with_vars')
docs: Parse a string for variables and interpolations, but don't treat
          anything else as Sass syntax.  Returns an AST node.