如何使用嵌套字典进行长度检查

data = {
    'username': {
        'value': 'john_doe',
        'min_length': 6,
        'max_length': 20
    },
    'password': {
        'value': 'password123',
        'min_length': 8,
        'max_length': 16
    },
    'email': {
        'value': 'john_doe@example.com',
        'min_length': 6,
        'max_length': 255
    }
}

def check_length(data):
    for field, info in data.items():
        value = info['value']
        min_length = info['min_length']
        max_length = info['max_length']
        length = len(value)
        
        if length < min_length or length > max_length:
            return False
    
    return True

result = check_length(data)
print(result)  # 输出：True