def METHOD_NAME(new_archive):
    """Check whether extras are not imported if the mode is set to 'none'"""
    imported_node = import_extras(new_archive, import_new_extras=False)
    with pytest.raises(AttributeError):
        # the extra 'b' should not exist
        imported_node.base.extras.get('b')
    with pytest.raises(AttributeError):
        # the extra 'c' should not exist
        imported_node.base.extras.get('c')