Computing a smallest (axis-aligned) rectangle that encloses a set of objects in the plane is a very common computational problem arising in graphics and thus game development too. Write a function, called min_enclosing_rectangle, that has 3 input parameters. The first is a number representing a radius of a circle and the next two are two numbers representing the x- and y-coordinates of its center. Consider the smallest axis-aligned rectangle that contains that circle. The function should return the x- and y-coordinates of the bottom-left corner of that rectangle. If side is a negative number, min_enclosing_rectangle should return None. The question should be done in python 3