Over the years, Stack Overflow (SO) has accumulated numerous code snippets, with developers going to SO for problem solutions and code references. However, in the case of the Python programming language, Python 3 is not necessarily backward compatible with Python 2. The major implication of this versioning problem is that code written in Python 2 may not be interpreted by Python 3 without modifications. This issue may affect the usability of Python code snippets on SO. We investigate how many Python code snippets on SO suffer from version compatibility issues, and find that about 10% of the snippets exhibit this problem. Moreover, of the code snippets that are interpretable only by Python 2 or Python 3, less than 17% are tagged with the Python version.

In this paper, we present a Chrome extension called PyVerDetector. This extension allows the user to select a given version of Python and verifies whether the code snippets on a given SO question are compatible with the user's selected Python version, providing error messages if not. The tool parses snippets and can determine versioning errors due to differences in syntax and also provides the user with a list of Python versions capable of interpreting each code snippet.