def METHOD_NAME():
    mydf = pd.DataFrame({'a': ['abc', u'xyz', '']})
    primitives_arr = anr._to_primitive(np.array(mydf.a.values), string_max_len=32)
    assert_array_equal(primitives_arr, np.array([u'abc', u'xyz', u''], dtype='U32'))
    assert primitives_arr.dtype == np.dtype('U32')