input: Write a python function to print a given string a specified number of times.
  assert print_string_n_times("Hello", 3) == "Hello\nHello\nHello\n"
  assert print_string_n_times("Hi", 2) == "Hi\nHi\n"
  assert print_string_n_times("Test", 5) == "Test\nTest\nTest\nTest\nTest\n"
output: def print_string_n_times(s: str, n: int) -> str:
      return (s + '\n') * n