ConstaLabs GST Preflight Python Client 0.1.0

Dependency-free Python 3 client for:
https://agent-gst-einvoice-api.constalabs.com

Run the live synthetic-data smoke test:
  python3 live_smoke.py

This tool performs technical validation and payload preparation only. It does
not submit to the Indian IRP, generate an IRN, or provide tax advice.
