input: Write a python function to extract elements that are at even positions (1-based index) in a list.
  assert extract_even_positions([1, 2, 3, 4, 5, 6]) == [2, 4, 6]
  assert extract_even_positions([10, 20, 30, 40, 50]) == [20, 40]
  assert extract_even_positions([5, 7, 9, 8, 6, 4, 3]) == [7, 8, 4]
output: def extract_even_positions(lst):
      return [lst[i] for i in range(1, len(lst), 2)]