'Like :func:`get_catalog` but using access URL look-up.
On multiple matches, only first match is returned.'

def get_catalog_by_url(self, url):

    keys = self._url_keys[url]
    if (len(keys) < 1):
        raise MissingCatalog(u"No    catalog    with    URL    '{0}'    found.".format(url))
    return VOSCatalog(self._catalogs[keys[0]])
