input: Write a function to check if a string `s` has matching parentheses. If the string has matching parentheses return True else return False.
  assert matching_paren("()") == True
  assert matching_paren("(())") == True
  assert matching_paren("()()") == True
  assert matching_paren("(()") == False
  assert matching_paren(")(") == False
output: def matching_paren(s):
      stack = []
      for char in s:
          if char == '(':
              stack.append(char)
          elif char == ')':
              if not stack:
                  return False
              stack.pop()
      return len(stack) == 0