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