input: Write a python function to split a string by the underscore '_' and print each word separately.
  assert split_and_print("hello_world") == ["hello", "world"]
  assert split_and_print("this_is_a_test") == ["this", "is", "a", "test"]
  assert split_and_print("split_by_underscore") == ["split", "by", "underscore"]
output: def split_and_print(s):
      return s.split('_')