How to use the ai2thor._builds.BUILDS function in ai2thor

def build_url(self):
        from ai2thor.build import arch_platform_map
        import ai2thor.build
        if platform.system() in BUILDS:
            return (BUILDS[platform.system()]['url'], BUILDS[platform.system()]['sha256'])
        else:
            url = None
            sha256_build = None
            git_dir = os.path.normpath(os.path.dirname(os.path.realpath(__file__)) + "/../.git")
            for commit_id in subprocess.check_output('git --git-dir=' + git_dir + ' log -n 10 --format=%H', shell=True).decode('ascii').strip().split("\n"):
                arch = arch_platform_map[platform.system()]

                try:
                    u = ai2thor.downloader.commit_build_url(arch, commit_id)
                    if os.path.isfile(self.executable_path(url=u)):
                        # don't need sha256 since we aren't going to download
                        url = u
                        break
                    elif ai2thor.downloader.commit_build_exists(arch, commit_id):
                        sha256_build = ai2thor.downloader.commit_build_sha256(arch, commit_id)
                        url = u

def build_image():

    version = nvidia_version()
    tag = ai2thor._builds.BUILDS['Docker']['tag']
    image_name = 'ai2thor/ai2thor-nvidia-%s:%s' % (version, tag)

    if image_exists(image_name):
        return image_name

    td = tempfile.mkdtemp()
    with open("%s/Dockerfile" % td, "w") as f:
        f.write(generate_dockerfile(tag))

    subprocess.check_call("docker build --rm -t %s %s" % (image_name, td), shell=True)

    shutil.rmtree(td)

    return image_name

def build_image():

    version = nvidia_version()
    tag = ai2thor._builds.BUILDS['Docker']['tag']
    image_name = 'ai2thor/ai2thor-nvidia-%s:%s' % (version, tag)

    if image_exists(image_name):
        return image_name

    td = tempfile.mkdtemp()
    with open("%s/Dockerfile" % td, "w") as f:
        f.write(generate_dockerfile(tag))

    subprocess.check_call("docker build --rm -t %s %s" % (image_name, td), shell=True)

    shutil.rmtree(td)

    return image_name