def _values(metadata, rel):
result = []<EOL>for r in metadata:<EOL><INDENT>if(r[REL] == rel):<EOL><INDENT>result.append(r[VAL])<EOL><DEDENT><DEDENT>return result<EOL>
Searches a set <metadata> to find all relations <rel>
    Returns a list of the values of those relations
    (A list, because a rel can occur more than once)