input: Write a function that optimizes the given Python script which reverses a string. The original script uses a loop to reverse the string character by character, while the optimized script should use a single-line method to achieve the same result.
  
  def reverse_string(string):
      return string[::-1]
  
  assert reverse_string("hello")=="olleh"
  assert reverse_string("Python")=="nohtyP"
  assert reverse_string("")==""
  assert reverse_string("12345")=="54321"
  assert reverse_string("a")=="a"
output: def reverse_string(string):
      return string[::-1]