Parse the value of a key-value pair.

def _parse_value(self):
        """Parse the value of a key-value pair."""
        indent = 0
        while self._cur_token['type'] is TT.ws:
            indent = self._skip_whitespace()
            self._skip_newlines()

        if self._cur_token['type'] is TT.id:
            return self._parse_key(indent)
        elif self._cur_token['type'] is TT.hyphen:
            self._increment()
            if self._cur_token['type'] is TT.hyphen:
                self._increment()
                return []
            else:
                return self._parse_object_list()
        else:
            # TODO: single comma gives empty list
            return self._parse_literal_list(indent)