def par_checker(symbol_string):
s = Stack()
balanced = True
index = 0
while index < len(symbol_string) and balanced:
symbol = symbol_string[index]
if symbol in '([{':
s.push(symbol)
else:
if s.isEmpth():
balanced = False
else:
top = s.pop()
if not matches(top, symbol):
balanced = False
index += 1
if balanced and s.isEmpty():
return True
else:
return False
