# TypeError: parse_requirement() missing 1 required positional argument: 'requirement_string'

- **ID:** `python/packaging-parse-requirement-error`
- **Domain:** python
- **Category:** type_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The function was called without the required string argument, likely due to incorrect API usage.

## 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)
   ```
   from packaging.requirements import Requirement; req = Requirement('requests>=2.0')
   ```
2. **** (85% success)
   ```
   help(Requirement)  # shows correct usage
   ```

## Dead Ends

- **** — An empty string is not a valid requirement; it will raise a different error. (90% fail)
- **** — Missing argument error persists regardless of passing style. (100% fail)