render method
values
can be a combination of Map, List, String. Any non-String object
will be converted using toString(). Null values will cause a
TemplateException, unless lenient module is enabled.
Implementation
void render(values, StringSink sink) {
var renderer = Renderer(sink, [values], _lenient, _htmlEscapeValues,
_partialResolver, _name, '', source);
renderer.render(_nodes);
}