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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 extract(domain):
 """ Extract newly added translations keys from source code. """

    translations_dir = _get_translations_dir()
    domain = _get_translations_domain(domain)
    babel_cfg = _get_babel_cfg()
    pot = os.path.join(translations_dir, f'{domain}.pot')
    return _run(f'extract -F {babel_cfg} -o {pot} .')