$border-radius: (
	'br-1': 2px,
	'br-2': 4px,
);

@function br($size) {

	@if not map-has-key($border-radius, $size) {
		@error "Invalid border radius size '#{$size}'. Must be one of: #{map-keys($border-radius)}.";
	}

	@return map-get($border-radius, $size);
}