def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def show_clusters(clusters, sample, covariances, means, figure=None, display=True):
        """!
        @brief Draws clusters and in case of two-dimensional dataset draws their ellipses.
        @details Allocated figure by this method should be closed using `close()` method of this visualizer.