Here's a neutral and interesting summary of the provided text in one paragraph: Python developers can utilize environment variables to configure their applications, eliminating the need for source code changes when configurations shift. The `os.environ` dictionary provides access to all environment variables, allowing Python programs to retrieve and use them as needed. Various methods exist for accessing environment variables, including using the `os.environ.get()` method, which returns a default value if the variable is not defined, or the `os.getenv()` function, which also does so without raising an error. Environment variables can be set in terminal sessions using the `export` keyword or by executing a script with the variable set. A more convenient approach is to store environment variables in a `.env` file, which can be imported into Python applications using the `python-dotenv` package, providing a uniform and organized way to manage configuration across platforms.