input: 
  from typing import List
  
  
  def matching_paren(s: str) -> bool:
      """Check if a string s has matching parentheses.
      >>> matching_paren("((()))")
      True
      >>> matching_paren("()()()")
      True
      >>> matching_paren("((())")
      False
      >>> matching_paren(")()(")
      False
      """
      stack: List[str] = []
      for char in s:
          if char == '(':
              stack.append(char)
          elif char == ')':
              if len(stack) == 0:
                  return False
              stack.pop()
      
      return len(stack) == 0
  
output:     stack: List[str] = []
      for char in s:
          if char == '(':
              stack.append(char)
          elif char == ')':
              if len(stack) == 0:
                  return False
              stack.pop()
      
      return len(stack) == 0