Complete the function diff do not modify the rest

Question

def diff(a,b):
    
# end function

print(" *** Find difference between A(x1,y1) and B(x2,y2) ***")
ins = input("Enter x1 y1 x2 y2 : ").split()
pointA= (int(ins[0]),int(ins[1]))
pointB= (int(ins[2]),int(ins[3]))
print("A B ==>",pointA,pointB)
print("Differnce from", pointA,"to", pointB,"==>",diff(pointA,pointB))
print("Differnce from", pointB,"to", pointA,"==>",diff(pointB,pointA))

output

 *** Find difference between A(x1,y1) and B(x2,y2) ***
Enter x1 y1 x2 y2 : 1 2 3 4
A B ==> (1, 2) (3, 4)
Differnce from (1, 2) to (3, 4) ==> (2, 2)
Differnce from (3, 4) to (1, 2) ==> (-2, -2)