Write a function to extract elements that occur singly in the given tuple list.
def extract_singly(test_list):
  res = []
  temp = set()
  for inner in test_list:
    for ele in inner:
      if not ele in temp:
        temp.add(ele)
        res.append(ele)
  return (res) 
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to extract elements that occur singly in the given tuple list.
def extract_singly(test_list):
  res = []
  temp = set()
  for inner in test_list:
    for ele in inner:
      if not ele in temp:
        temp.add(ele)
        res.append(ele)
  return (res) [/INST]assert extract_singly([(3, 4, 5), (4, 5, 7), (1, 4)]) == [3, 4, 5, 7, 1]
assert extract_singly([(1, 2, 3), (4, 2, 3), (7, 8)]) == [1, 2, 3, 4, 7, 8]
assert extract_singly([(7, 8, 9), (10, 11, 12), (10, 11)]) == [7, 8, 9, 10, 11, 12]</s>