def METHOD_NAME():
    data_new = copy.deepcopy(data_dict)
    put_value(data_new, 'a.b', 1)
    assert 1 == get_field_value(data_new, 'a.b')
    put_value(data_new, '.a.b', 2)
    assert 2 == get_field_value(data_new, 'a.b')
    put_value(data_new, 'm.n.o', {'a': {'b': 'c'}})
    assert {'a': {'b': 'c'}} == get_field_value(data_new, 'm.n.o')