# ERROR: Invalid requirement: 'package<1.0,>=2.0'

- **ID:** `python/pip-invalid-requirement-format`
- **Domain:** python
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The requirement string has conflicting version constraints that cannot be satisfied simultaneously.

## Version Compatibility

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

## Workarounds

1. **Correct the version range to be non-contradictory** (95% success)
   ```
   pip install 'package>=1.0,<2.0'
   ```
2. **Use a single version constraint** (90% success)
   ```
   pip install 'package>=1.0'
   ```

## Dead Ends

- **Reordering the constraints (e.g., '>=2.0,<1.0')** — The conflict remains regardless of order; pip parses the entire set. (95% fail)
- **Using a comma instead of a semicolon** — Commas are valid separators; the issue is the logical contradiction. (90% fail)