ParseRequirements parses requirements.

Untar takes a destination path and a reader; a tar reader loops over the tarfile creating the file structure at 'dst' along the way, and writing any files.

Unzip will decompress a zip archive, moving all files and folders within the zip file (parameter 1) to an output directory (parameter 2).

Requirement represents a Python requirement.

Specifier is like this thing maybe?: https://www.python.org/dev/peps/pep-0508/.