def parseQuery(query):
    """Parse a query string.

        Return a parse tree (which implements IQueryParseTree).

        Some of the query terms may be ignored because they are
        stopwords; use getIgnored() to find out which terms were
        ignored.  But if the entire query consists only of stop words,
        or of stopwords and one or more negated terms, an exception is
        raised.

        May raise ParseTree.ParseError.
        """
