How to use the dagster.lambda_solid function in dagster

@lambda_solid(
    input_defs=[InputDefinition('num', PoorMansDataFrame)],
    output_def=OutputDefinition(PoorMansDataFrame),
)
def sum_solid(num):
    sum_df = deepcopy(num)
    for x in sum_df:
        x['sum'] = x['num1'] + x['num2']
    return PoorMansDataFrame(sum_df)

    @lambda_solid(output_def=OutputDefinition(Int))
    def return_one():
        return 1

    @lambda_solid(input_defs=[InputDefinition('num_one'), InputDefinition('num_two')])
    def add(num_one, num_two):
        return num_one + num_two

@lambda_solid
def do_something():
    return 1

    @lambda_solid()
    def first():
        return ['first']

    @lambda_solid
    def user_throw_exception():
        raise Exception('whoops')

@lambda_solid
def produce_invalid_ssn_string():
    return '394-30-203239483'

    @lambda_solid(output_def=OutputDefinition(list))
    def emit_list():
        return [1]

    @lambda_solid(input_defs=[InputDefinition('num')])
    def div_two(num):
        return num / 2

    @lambda_solid
    def return_two():
        return 2