如何在没有大量重复检查代码的情况下处理函数的多个可能的早期返回

function processUser(user) {
    if (!user) {
        return 'User not found';
    }
    if (!user.isActive) {
        return 'User is inactive';
    }
    if (!user.isVerified) {
        return 'User is not verified';
    }
    // 继续处理已验证且活跃的用户
    return 'User processed successfully';
}

class User:
    def process(self):
        raise NotImplementedError

class ActiveUser(User):
    def process(self):
        return 'Active user processed'

class InactiveUser(User):
    def process(self):
        return 'Inactive user processed'

def process_user(user):
    return user.process()

interface UserProcessingStrategy {
    String process(User user);
}

class ActiveUserProcessingStrategy implements UserProcessingStrategy {
    public String process(User user) {
        return "Active user processed";
    }
}

class InactiveUserProcessingStrategy implements UserProcessingStrategy {
    public String process(User user) {
        return "Inactive user processed";
    }
}

class UserProcessor {
    private UserProcessingStrategy strategy;

    public void setStrategy(UserProcessingStrategy strategy) {
        this.strategy = strategy;
    }

    public String process(User user) {
        return strategy.process(user);
    }
}

def process_user(user):
    return (
        'User not found' if not user else
        'User is inactive' if not user.isActive else
        'User is not verified' if not user.isVerified else
        'User processed successfully'
    )