python-json-patch is a Python library implementing the JSON Patch format (RFC 6902) for applying operations like add, remove, replace, move, copy, and test to JSON documents. It includes a smart diff algorithm to generate minimal patches by comparing two JSON objects, and provides command-line utilities (jsondiff and jsonpatch) for file-based operations. The core logic resides in jsonpatch.py, which is self-contained aside from the jsonpointer dependency, and handles edge cases such as duplicate keys via a custom multidict function. The library supports Python 2.7 and 3.7+ (though its setup.py contains an version specifier error excluding 3.4-3.6).