<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def main():
 """ Small run usage exemple """

    #TODO: need to be mv in .rst doc
    from reliure.pipeline import Composable
    @Composable
    def doc_analyse(docs):
       for doc in docs:
            yield {
                "title": doc,
                "url": "http://lost.com/%s" % doc,
            }

    @Composable
    def print_ulrs(docs):
        for doc in docs:
            print(doc["url"])
            yield doc

    pipeline = doc_analyse | print_ulrs

    documents = ("doc_%s" % d for d in xrange(20))
    res = run_parallel(pipeline, documents, ncpu=2, chunksize=5)
    print(res)