def _handle_template_param_value(self):
        """Handle a template parameter's value at the head of the string."""
        self._emit_all(self._pop())
        self._context ^= contexts.TEMPLATE_PARAM_KEY
        self._context |= contexts.TEMPLATE_PARAM_VALUE
        self._emit(tokens.TemplateParamEquals())
Handle a template parameter's value at the head of the string.