input: Write a python function to print all elements of a list, each followed by a space.
  assert print_list([1, 2, 3, 4, 5]) == "1 2 3 4 5 "
  assert print_list([10, 20, 30]) == "10 20 30 "
  assert print_list([7, 14, 21]) == "7 14 21 "
output: def print_list(lst):
      return ' '.join(map(str, lst)) + ' '