def generator_test1():
  # 0...9 generator
  x = (i for i in range(10))
  # 5..9 generator
  x_filter = filter(lambda y: y >= 5, x)
  # first use the x
  L = list(x)
  print("L, x", L)
  # then use x_filter
  l = list(x_filter)
  print("l, x_filter", l)
if __name__ == "__main__":
  generator_test1()

def generator_test2():
  x = (i for i in range(10))
  for i in range(10):
    x = (j + i for j in x)
  L = list(x)
  print("L, x", L)
if __name__ == "__main__":
  generator_test2()

def generator_test3():
  x = (i for i in range(10))
  for i in range(10):
    x = (j + i for j in x)
  i = 20
  L = list(x)
  print("L, x", L)
 
if __name__ == "__main__":
  generator_test3()