Check for balanced parentheses in an expression

balanced_paranthesis.py

def braces_validator(string):
    openers = "({["
    closers = ")}]"    
    stack = []    
    for char in string:
        if char in openers:
            stack.append(openers.index(char))
        elif char in closers:
            if len(stack) == 0 or stack.pop() != closers.index(char):
                return False
    return len(stack) == 0

# Testing
print braces_validator("(((((({ [ ] ( ) }")
print braces_validator("{ [ ( ] ) }))))))")
print braces_validator("")
print braces_validator("({[]})")
print braces_validator("({[]})]")