Portage API - Return all packages available in given Overlay [Gentoo Linux]

overlay.py

import portage
from gentoolkit.package import Package

def get_all_packages(overlay_path):
    """Returns all packages from a given overlay path.
    """
    packages = {}
    porttree = portage.db[portage.root]['porttree']
    vartree = portage.db[portage.root]['vartree']

    if overlay_path not in porttree.dbapi.porttrees:
        print('Overlay "%s" is not set in PORTDIR_OVERLAY.\n' % overlay_path +
        'Please add it in /etc/make.conf and try again.')
        return False

    for cp in porttree.dbapi.cp_all(trees=[overlay_path]):
        for cpv in porttree.dbapi.cp_list(cp, mytree=[overlay_path]):
            packages[cpv] = Package(cpv)
        for cpv in vartree.dbapi.cp_list(cp):
            # Insert only a new entry if not overriding an existing one.
            packages.setdefault(cpv, Package(cpv))

    return packages

packages = get_all_packages('/var/lib/layman/noiselabs')