def is_email(value):

    if value is None:
        return

    if not re.match(r'\S+@\S+\.\S+', value):
        return c('email')
configure() will create the package dir if it doesn't exist
dataset/ETHPy150Open heiskr/sagefy/server/modules/validations.py/is_email--crossover with--dataset/ETHPy150Open mathcamp/pypicloud/tests/test_storage.py/TestFileStorage.test_create_package_dir