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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def download_command(args):
 """Downloads and extracts the latest App Engine SDK to the given destination."""

    latest_two_versions = list(reversed(get_gae_versions()))[:2]

    zip = None
    version_number = None

    for version in latest_two_versions:
        if is_existing_up_to_date(args.destination, version[0]):
            print(
                'App Engine SDK already exists and is up to date '
                'at {}.'.format(args.destination))
            return

        try:
            print('Downloading App Engine SDK {}'.format(
                '.'.join([str(x) for x in version[0]])))
            zip = download_sdk(version[1])
            version_number = version[0]
            break
        except Exception as e:
            print('Failed to download: {}'.format(e))
            continue

    if not zip:
        return

    print('Extracting SDK to {}'.format(args.destination))

    extract_zip(zip, args.destination)
    fixup_version(args.destination, version_number)

    print('App Engine SDK installed.')