Render template lines.

        Note: we only need to parse the namespace if we used variables in
              this part of the template.

def render(self, namespace):
        '''Render template lines.

        Note: we only need to parse the namespace if we used variables in
              this part of the template.
        '''
        return self._text.format_map(namespace.dictionary) \
            if self._need_format else self._text