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

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

## Root Cause

The requirement string has malformed version specifiers or invalid characters.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.8 | active | — | — |
| 3.9 | active | — | — |

## Workarounds

1. **Use correct PEP 440 specifiers** (90% success)
   ```
   pip install 'package_name>=1.0,<2.0' (with proper spaces)
   ```
2. **Check for typos in package name** (70% success)
   ```
   Ensure no spaces in name
   ```

## Dead Ends

- **Removing version specifiers entirely** — May install incompatible version. (40% fail)
- **Using single equals sign** — Incorrect syntax. (60% fail)