def lookup_claimReview_url(url, claimReview_db):
    """Looks up a URL for a ClaimReview in our DB

    :param url: str URL value for a ClaimReview
    :param claimReview_db: a ClaimReview database
    :returns: a dict
    :rtype: dict
    """
    assert type(claimReview_db) is dict, '%s' % (type(claimReview_db))
    assert claimReview_db.get('@type') == 'InMemoryClaimReviewDB'
    idx = claimReview_db.get('url2doc_index', {}).get(url, None)
    if idx:
        return claimReview_db['docs'][idx]
    else:
        return None