def get_root():
    """Get the project root directory.

    We require that all commands are run from the project root, i.e. the
    directory that contains setup.py, setup.cfg, and versioneer.py .
    """
    root = os.path.realpath(os.path.abspath(os.getcwd()))
    setup_py = os.path.join(root, "setup.py")
    versioneer_py = os.path.join(root, "versioneer.py")
    if not (os.path.exists(setup_py) or os.path.exists(versioneer_py)):
        # allow 'python path/to/setup.py COMMAND'
        root = os.path.dirname(os.path.realpath(os.path.abspath(sys.argv[0])))
        setup_py = os.path.join(root, "setup.py")
        versioneer_py = os.path.join(root, "versioneer.py")
    if not (os.path.exists(setup_py) or os.path.exists(versioneer_py)):
        err = ("Versioneer was unable to run the project root directory. "
               "Versioneer requires setup.py to be executed from "
               "its immediate directory (like 'python setup.py COMMAND'), "
               "or in a way that lets it use sys.argv[0] to find the root "
               "(like 'python path/to/setup.py COMMAND').")
        raise VersioneerBadRootError(err)
    try:
        # Certain runtime workflows (setup.py install/develop in a setuptools
        # tree) execute all dependencies in a single python process, so
        # "versioneer" may be imported multiple times, and python's shared
        # module-import table will cache the first one. So we can't use
        # os.path.dirname(__file__), as that will find whichever
        # versioneer.py was first imported, even in later projects.
        my_path = os.path.realpath(os.path.abspath(__file__))
        me_dir = os.path.normcase(os.path.splitext(my_path)[0])
        vsr_dir = os.path.normcase(os.path.splitext(versioneer_py)[0])
        if me_dir != vsr_dir and "VERSIONEER_PEP518" not in globals():
            print("Warning: build in %s is using versioneer.py from %s"
                  % (os.path.dirname(my_path), versioneer_py))
    except NameError:
        pass
    return root
Get the project root directory.

    We require that all commands are run from the project root, i.e. the
    directory that contains setup.py, setup.cfg, and versioneer.py .
    
versioneer.py