how to insert a value at an index in python code example

Example 1: append to lists python

list = ['a', 'b', 'c', 'd']
  print list[1:-1]   ## ['b', 'c']
  list[0:2] = 'z'    ## replace ['a', 'b'] with ['z']
  print list         ## ['z', 'c', 'd']

Example 2: append to list at index python

#!/usr/bin/python

aList = [123, 'xyz', 'zara', 'abc']
aList.insert( 3, 2009)
print "Final List : ", aList