margin method
Implementation
Container margin(
{double left: 0,
double top: 0,
double right: 0,
double bottom: 0,
vertical,
horizontal}) =>
Container(
margin: vertical != null || horizontal != null
? EdgeInsets.symmetric(
vertical: vertical ?? 0, horizontal: horizontal ?? 0)
: EdgeInsets.only(
left: left, top: top, right: right, bottom: bottom),
child: this,
);