Simpson's rule in Python

Question

For a numerical methods class, I need to write a program to evaluate a definite integral with Simpson\'s composite rule. I already got this far (see below), but my answer is

Answer 1

def simps(f, a, b, N):   # N must be an odd integer
    """ define simpson method, a and b are the lower and upper limits of
    the interval, N is number of points, dx is the slice
        """
    integ = 0
    dx = float((b - a) / N)

    for i in range(1,N-1,2):
        integ += f((a+(i-1)*dx)) + 4*f((a+i*dx)) + f((a+(i+1)*dx))
        integral = dx/3.0 * integ
    
    # if number of points is even, then error araise
    if (N % 2) == 0:
      raise ValueError("N must be an odd integer.")
        

    return integral


def f(x):
    return x**2


integrate = simps(f,0,1,99)
print(integrate)