input: Write a function to print unique elements from a given list. If the list is empty, print nothing.
  def print_unique(my_list):
      seen = set()
      for x in my_list:
          if x not in seen:
              print(x)
              seen.add(x)
  assert print_unique([1, 2, 2, 3, 4, 4])
  # Expected Output: 1\n2\n3\n4\n
  assert print_unique([1, 1, 1, 1])
  # Expected Output: 1\n
  assert print_unique([])
  # Expected Output: (No output)
output: def print_unique(my_list):
      seen = set()
      for x in my_list:
          if x not in seen:
              print(x)
              seen.add(x)