input: Write a python function to classify items into cheap and expensive categories.
  assert classify([('fruit', 2.5), ('beer', 10), ('shampoo', 3), ('chocolate', 6)]) == ([('fruit', 2.5), ('shampoo', 3)], [('beer', 10), ('chocolate', 6)])
  assert classify([('apple', 1), ('milk', 4), ('bread', 6), ('wine', 12)]) == ([('apple', 1), ('milk', 4)], [('bread', 6), ('wine', 12)])
  assert classify([('pen', 0.5), ('notebook', 2), ('laptop', 1000), ('phone', 800)]) == ([('pen', 0.5), ('notebook', 2)], [('laptop', 1000), ('phone', 800)])
output: def classify(items):
      cheap = []
      expensive = []
      for item in items:
          if item[1] <= 5:
              cheap.append(item)
          else:
              expensive.append(item)
      return (cheap, expensive)