input: Write a function to optimize a given Python script that reverses a string. The input function uses a loop to reverse the string character by character, and the output function uses Python's slicing feature to achieve the same result in a more efficient manner.
  
  ### Input:
  def reverse_string(string):
      reversed_string = ""
      for char in string:
          reversed_string = char + reversed_string
      return reversed_string
  
  ### Output:
  def reverse_string(string):
      return string[::-1]
  
  assert reverse_string("hello")=="olleh"
  assert reverse_string("Python")=="nohtyP"
  assert reverse_string("")==""
  assert reverse_string("a")=="a"
  assert reverse_string("12345")=="54321"
output: def reverse_string(string):
      return string[::-1]