new_contents: #!/usr/local/bin/python
  matrix=[[1,2,3],[4,5,6],[7,8,9]]
  x1=[x for row in matrix for x in row]
  print x1
  #x2=[x for i in sublist for sublist in matrix]
  #print x2
  y1=[y for y in row for row in matrix]
  print y1
  y2=[[y for y in row] for row in matrix]
  print y2
  squared=[[x**2 for x in row] for row in matrix]
  print squared
  a=[1,2,3,4,5,6,7,8,9,10]
  b=[x for x in a if x>4 if x%2==0]
  c=[x for x in a if x>4 and x%2==0]
  print b
  print c
  f=[[x for x in row if x%3==0] for row in matrix if sum(row)>=9]
  print f
  
subject: Add item8.