# ERROR: option --extra-index-url requires an argument

- **ID:** `python/pip-option-requires-argument`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The --extra-index-url flag was used without providing a URL value.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.8 | active | — | — |
| 3.9 | active | — | — |
| 3.10 | active | — | — |
| 3.11 | active | — | — |
| 3.12 | active | — | — |

## Workarounds

1. **** (95% success)
   ```
   pip install package --extra-index-url https://private-pypi.example.com/simple
   ```
2. **** (90% success)
   ```
   export PIP_EXTRA_INDEX_URL=https://private-pypi.example.com/simple && pip install package
   ```

## Dead Ends

- **** — Pip will try to use that URL and fail to connect. (80% fail)
- **** — The package may not be found without the extra index. (50% fail)