Base form rule. All form formatting rules should derive from BaseRule.
Nested rule. Can contain child rules and render them.
Constructor.
Render text (or HTML snippet) from string.
Shortcut for Text rule with escape set to `False.
Render macro by its name from current Jinja2 context.
Render container around child rule.
Form field rule.
Render header text.
Field set with header.
Enter search terms or a module, class or function name.