gistfile1.txt

```swift
⭕️
observable1.flatMap { [weak self] ... in
    print(self?.value)
    return observable2.flatMap { ... in in
        print(self?.value)
    }
}

⭕️
observable1.flatMap { [weak self] ... in
    guard let self = self else { return .empty() }
    print(self.value)
    return observable2.flatMap { [weak self] ... in in
        print(self?.value)
    }
}

⭕️
observable1.flatMap { [weak self] ... in
    print(self?.value)
    return observable2.flatMap { ... in in
        guard let self = self else { return .empty() }
        print(self.value)
    }
}

⭕️
observable1.flatMap { [weak self] ... in
    guard let self = self else { return .empty() }
    print(self.value)
    return observable2.flatMap { [weak self] ... in in
        guard let self = self else { return .empty() }
        print(self.value)
    }
}

⭕️ // But might cause crash 💥
observable1.flatMap { [unowned self] ... in
    print(self.value)
    return observable2.flatMap { ... in in
        print(self.value)
    }
}

❌ // No guarantee that there won't be any retain-cycles. It depends on other factors.
observable1.flatMap { ... in
    print(self.value)
    return observable2.flatMap { ... in in
        print(self.value)
    }
}

❌ // No guarantee that there won't be any retain-cycles. It depends on other factors.
observable1.flatMap { [weak self] ... in
    guard let self = self else { return .empty() }
    print(self.value)
    return observable2.flatMap { ... in in
        print(self.value)
    }
}
```