# Source: https://docs.datadoghq.com/security/code_security/static_analysis/static_analysis_rules/python-best-practices/exception-inherit.md

---
title: ensure exception inherit a base exception
description: Datadog, the leading service for cloud-scale monitoring.
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  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > ensure exception inherit a base exception
---

# ensure exception inherit a base exception

{% callout %}
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{% alert level="danger" %}
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{% /callout %}

## Metadata{% #metadata %}

**ID:** `python-best-practices/exception-inherit`

**Language:** Python

**Severity:** Warning

**Category:** Best Practices

## Description{% #description %}

New `Exception` must inherit the base `Exception`. Always use another exception as parent or use at least the `Exception` base class.

#### Learn More{% #learn-more %}

- [Python Documentation: User-defined Exceptions](https://docs.python.org/3/tutorial/errors.html#user-defined-exceptions)

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```python
class CustomException:
    """An Invalid exception class."""
```

## Compliant Code Examples{% #compliant-code-examples %}

```python
class CustomException(Exception):
    """An Invalid exception class."""
```
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