def get_version(exe_path='youtube-dl'):
    '''Get the version string of youtube-dl.'''
    process = subprocess.Popen(
        [exe_path, '--version'],
        stdout=subprocess.PIPE
    )
    version_string = process.communicate()[0]
    version_string = version_string.decode().strip()

    assert ' ' not in version_string, version_string

    return version_string
Get the version string of youtube-dl.