How to use the omegaml.store.query.MongoQ function in omegaml

Specify either the __query or the kwargs. If __query is
        specified it is returned unchanged. If kwargs is passed these
        are used to build a new MongoQ object. The rationale for this
        is so that build_query can be used without an if statement in
        the calling code (i.e. this methods wraps the if statement on
        whether to build a new MongoQ object or to use the existing,
        making for more readable code).

        :param __query: the MongoQ object to use
        :param kwargs: the filter as a dict of column__op=value pairs
        :return: the MongoQ object
        """
        if __query:
            q = __query
        else:
            q = MongoQ(**kwargs)
        return q

stop -= int(self.positional)
                            flt_kwargs['{}__lte'.format(col)] = stop
                    elif isinstance(spec, enumerable_types) and isscalar(spec[0]):
                        self._from_range = True
                        # single column index with list of scalar values
                        # -- convert to list for PyMongo serialization
                        if isinstance(spec, np.ndarray):
                            spec = spec.tolist()
                        flt_kwargs['{}__in'.format(col)] = spec
                    elif isscalar(col):
                        flt_kwargs[col] = spec
                else:
                    # we're out of index columns, let's look at columns
                    projection.extend(self._get_projection(spec))
        if flt_kwargs:
            filterq.append(MongoQ(**flt_kwargs))
        finalq = None
        for q in filterq:
            if finalq:
                finalq |= q
            else:
                finalq = q
        return finalq, projection

def _get_filter_criteria(self, *args, **kwargs):
        """ 
        return mongo query from filter specs

        this uses a Filter to produce the query from the kwargs.

        :param args: a Q object or logical combination of Q objects
           (optional)
        :param kwargs: all AND filter criteria 
        """
        if len(args) > 0:
            q = args[0]
            if isinstance(q, MongoQ):
                filter_criteria = Filter(self.collection, q).query
            elif isinstance(q, Filter):
                filter_criteria = Filter(self.collection, q.q).query
        else:
            filter_criteria = Filter(self.collection, **kwargs).query
        return filter_criteria