input: from typing import List
  
  
  def reverse_string(string):
      """
      Optimize the given function that reverses a string. The function should use a more efficient approach to reverse the input string.
      
      >>> reverse_string("hello")
      'olleh'
      >>> reverse_string("Python")
      'nohtyP'
      """
      return string[::-1]
output:     return string[::-1]