@op
def return_b(arg):
    return arg + "b"
def return_a(arg):
    return arg + "a"


def c(init_arg='hello', fn=(return_a, return_b)):
    next_step = None
    for next_step in fn:
        prev_step=next_step or init_arg
        next_step(prev_step)
        
# expected_output = return_a(return_b('hello'))

def op_factory(steps) -> OpDefinition:

    for step in steps:
        if step[:6] == 'import':
            @op(name=step, **kw)
            def importer():
                print("import stuff")
            yield importer

        elif step == 'parquet':
            @op(name=step, **kw)
            def to_parquet():
                print("transform stuff")
            yield to_parquet