def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def get_target_input(module, input, output):
    """A forward hook which saves the tensor - attached to its graph.
    Used if we want to explain the interim outputs of a model
    """
    try:
        del module.target_input
    except AttributeError:
        pass
    setattr(module, 'target_input', input)