def common_ancestor(c):
span1 = _to_span(c[<NUM_LIT:0>])<EOL>span2 = _to_span(c[<NUM_LIT:1>])<EOL>ancestor1 = np.array(span1.sentence.xpath.split("<STR_LIT:/>"))<EOL>ancestor2 = np.array(span2.sentence.xpath.split("<STR_LIT:/>"))<EOL>min_len = min(ancestor1.size, ancestor2.size)<EOL>return list(ancestor1[: np.argmin(ancestor1[:min_len] == ancestor2[:min_len])])<EOL>
Return the path to the root that is shared between a binary-Mention Candidate.

    In particular, this is the common path of HTML tags.

    :param c: The binary-Mention Candidate to evaluate
    :rtype: list of strings