input: Write a python function to get the third character from each word in a list.
  assert third_char(['IronMan', 'Hulk', 'Thor', 'Captain America']) == 'onp'
  assert third_char(['apple', 'banana', 'cherry']) == 'pnc'
  assert third_char(['a', 'b', 'c']) == ''
output: def third_char(words):
      return ''.join(word[2] for word in words if len(word) >= 3)