RestrictedPython is a tool for defining a subset of the Python programming language that allows running untrusted code in a controlled environment. It’s not a full sandbox, but it creates a trusted space where potentially harmful code can be executed safely. The tool is designed to work specifically with CPython, meaning it doesn't support other Python implementations like PyPy. This limitation is important for developers who need to ensure their code runs without the risk of breaching security. The article provides two examples to illustrate the functionality of RestrictedPython. In the first example, a simple function that returns "Hello World!" is safely executed without any risk to the system. This highlights how the tool can manage benign code effectively. However, the second example demonstrates a potential threat: attempting to import the `os` module to list directory contents is blocked, resulting in an ImportError. This emphasizes RestrictedPython's ability to prevent certain operations that could compromise security. For those interested in contributing to RestrictedPython, the article points to a documentation page specifically for contributors. The focus is on maintaining and improving the tool's functionality, which is vital for developers who rely on it for secure code execution. The clear examples and practical advice make it easy to understand how RestrictedPython functions and its significance in secure programming practices.