<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def update_ontology(ont_url, rdf_path):
 """Load an ontology formatted like Eidos' from github."""

    yaml_root = load_yaml_from_url(ont_url)
    G = rdf_graph_from_yaml(yaml_root)
    save_hierarchy(G, rdf_path)