def insert(self, doc, synced=False):
        doc.id = self.get_next_id()
        doc.synced = synced
        try:
            self.db.docs.insert(doc)
        except Exception as e:
            raise DatabaseException(e)
        return doc
def initialize(self, init_type = ema_init_type.KMEANS_INITIALIZATION):
        """!
        @brief Calculates initial parameters for EM algorithm: means and covariances using
                specified strategy.