> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://documentation.celestory.io/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# ⬜ No  Reverse

# ⬜ No  Reverse

The **No / Invert** block allows you to invert a Boolean value (True/False).

This block is essential for creating negative logic conditions, such as checking that a condition is not met before performing an action.

## 📥 Entries

* **value (Boolean)**: The Boolean value to invert, which may come from a condition or a variable.

## 📤 Outings

* **value (Boolean)**: The inverted value (True becomes False, False becomes True).

## 💡 Example of use

**Scenario: Prevent access to a secure area without a badge**

1. A user attempts to open a secure door.
2. The system checks if the variable `aBadge` is `True` (the user has a valid badge).
3. The value of `aBadge` is connected to the **value** input of the **No** block.
4. The output of the **No** block is linked to a condition that triggers an alert.
5. *Behavior*:
* If `aBadge` = `False` (no badge), the **No** block returns `True` → the alert is triggered.
* If `aBadge` = `True` (valid badge), the **No** block returns `False` → access is authorized.

## ⚙️ Technical Details
* **Logic operation**: Pure inversion (`!value` in programming), compatible only with Boolean data.
* **Error handling**: If a non-Boolean value is provided, the block returns `False` by default.