def download_options(dataset, node, entityids, api_key=None):
    
    root, body = create_root_request()
    
    el = create_request_type(body, "downloadOptions")
    
    create_dataset_element(el, dataset)
    create_node_element(el, node)
    
    if api_key:
        create_api_key_element(el, api_key)
    
    create_entity_ids_element(el, entityids)
    
    return tostring(root)
Basic validation of Google Storage paths.
dataset/ETHPy150Open mapbox/usgs/usgs/soap.py/download_options--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/cloudstorage/common.py/_validate_path