input: Write a python function to print elements at even indices.
  assert print_even_indices([10, 20, 30, 40, 50, 60])==None # Expected output: 10 30 50
  assert print_even_indices([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])==None # Expected output: 1 3 5 7 9
  assert print_even_indices(['a', 'b', 'c', 'd', 'e', 'f'])==None # Expected output: 'a' 'c' 'e'
output: def print_even_indices(lst):
      for i in range(0, len(lst), 2):
          print(lst[i])