# File lib/maruku/ext/math/to_html.rb, line 47
      def render_mathml(kind, tex)
        engine = get_setting(:html_math_engine)
        method = "convert_to_mathml_#{engine}"
        if self.respond_to? method
          mathml = self.send(method, kind, tex)
          return mathml || convert_to_mathml_none(kind, tex)
        end

        # TODO: Warn here
        raise "A method called #{method} should be defined."
        convert_to_mathml_none(kind, tex)
      end