Create a function that takes numbers b, m, and n as arguments and returns the definite integral of the function f(x)=(b+1)*x^b with respect to x from x=m to x=n, where b, m, and n are constants.
integral(0, 2, 5) ➞ 3
integral(2, 4, 7) ➞ 279
integral(5, 9, 3) ➞ -530712
^ in the context of this challenge means "to the power of", also known as the "exponent" operator.b will be an integer greater than or equal to 0.m and n can be any integer, both positive and negative.