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 literal_eval(node_or_string):
    if isinstance(node_or_string, AST):
        node_or_string = gast_to_ast(node_or_string)
    return _ast.literal_eval(node_or_string)