Example analysis of python implementation of Simpson's method for numerical integration

#coding = utf-8
#simpson's method of integrals, numerical integration, works like a charm.
from math import *
def func(x): 
 """
 Define the integrated function
 """
 return x*sin(x)
def Get_N(a,b,width):
 # width is the step size
 N=int((b-a)/width + 1)
 if N%2 == 0:
  N=N+1
 return N
def GenerateData(a,b,n,width):
 datas = []
 r=a
 for i in range(0,n):
  (func(r))
  r = r+width
 return datas
def simpson_integral(datas,width,n):
 sum = datas[0]+datas[n-1]
 for i in range(2,n):
  if i%2== 0:
   sum = sum +4*datas[i-1]
  else:
   sum = sum +2*datas[i-1]
 return sum*width/3.0
if __name__ == "__main__":
 a=1.0 #Points cap
 b=3.0 # Lower limit of points
 width=0.0625 #Steps
 N=Get_N(a,b,width)
 datas = GenerateData(a,b,N,width)
 print simpson_integral(datas,width,N)