What packaging solves
Packaging defines how Python code is installed and distributed. Modern projects commonly use pyproject.toml for project metadata, build configuration and dependency declarations.
Separate project metadata from application code
Package metadata can describe the project name, version, supported Python versions, dependencies and command-line entry points. This allows a clean environment to install the application without relying on a developer's workstation.
Build and test artifacts
Source distributions and wheels are common distribution formats. Building the package and installing it into a clean environment is a valuable verification step because it catches missing package files and incorrect metadata.
Practice: create a minimal package containing one reusable function, define its metadata in pyproject.toml and install it into a fresh environment.