new_contents: #!/usr/bin/env python2
  
  '''
  Generates automatically two arrays, a and b.
  Return an arrays containing common elements in arrays
  a and b.
  '''
  
  import random
  
  SIZE_LIST_A = 10
  SIZE_LIST_B = 20
  a = []
  b = []
  
  
  def populate_arrays():
    for i in range(0, SIZE_LIST_A):
      a.append(random.randint(1, 100))
    for i in range(0, SIZE_LIST_B):
      b.append(random.randint(1, 100))
  
  def return_list(a, b):
    c = []
    for i in a:
      if i in b and i not in c:
        c.append(i)
    return c
  
  
  if __name__ == "__main__":
    populate_arrays()
    print "a: {:s}".format(str(a))
    print "b: {:s}".format(str(b))
    c = return_list(a, b)
    if len(c) > 0:
      print "c: {:s}".format(str(c))
    else:
      print "nothing in comon"
  
  exit(0)
  
subject: Create lists.py