def get_rect_xmin(data):
 return min(data[0][0], data[1][0], data[2][0], data[3][0])

def get_rect_xmin ( data ) : return min ( data [ 0 ] [ 0 ] , data [ 1 ] [ 0 ] , data [ 2 ] [ 0 ] , data [ 3 ] [ 0 ] )
find minimum x value from four vertices .