get app engine Query decoded to string

show_query.py

def show_query(query):
    """
    Represent a query as a string
    Based on http://kupuguy.googlecode.com/svn/trunk/appengine-doctests/showquery.py
    """
    from google.appengine.api import datastore

    kind = query._model_class.kind()
    ancestor = query._Query__ancestor
    filters = query._Query__query_sets[0]
    orderings = query._Query__orderings

    res = ["%s.all()" % kind]
    if ancestor is not None:
        res.append("ancestor(%r)" % ancestor)
    for k in sorted(filters):
        res.append("filter(%r, %r)" % (k, filters[k]))
    for p, o in orderings:
        if o==datastore.Query.DESCENDING:
            p = '-'+p
        res.append("order(%r)" % p)

    return '.'.join(res)