type Container = {
child: &Widget,
padding: &Padding,
width: &Length,
height: &Length,
halign: &HAlign,
valign: &VAlign
};
val container: fn(
?#padding: &Padding,
?#width: &Length,
?#height: &Length,
?#halign: &HAlign,
?#valign: &VAlign,
child: &Widget
) -> Widget