<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def update(domain):
 """ Update language-specific translations files with new keys discovered by ``flask babel extract``. """

    translations_dir = _get_translations_dir()
    domain = _get_translations_domain(domain)
    pot = os.path.join(translations_dir, f'{domain}.pot')
    return _run(f'update -i {pot} -d {translations_dir} --domain={domain}')