If you want to contribute anything to parso, just open an issue or pull request to discuss it. We welcome changes! Please check the file in the repository, first.

Deprecations Process

The deprecation process is as follows:

  1. A deprecation is announced in the next major/minor release.
  2. We wait either at least a year & at least two minor releases until we remove the deprecated functionality.


The test suite depends on tox and pytest:

pip install tox pytest

To run the tests for all supported Python versions:


If you want to test only a specific Python version (e.g. Python 2.7), it’s as easy as:

tox -e py27

Tests are also run automatically on Travis CI.