input: Write a function to determine if a string s has matching parentheses. If it is possible return True else return False. If the string is empty then return True.
  
  assert matching_paren("(())")==True
  assert matching_paren("(()")==False
  assert matching_paren("()()")==True
  assert matching_paren("(()))")==False
  assert matching_paren("")==True
output: def matching_paren(s):
      count = 0
      for char in s:
          if char == '(':
              count += 1
          elif char == ')':
              count -= 1
          if count < 0:
              return False
      return count == 0