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 ngettext(self, singular: str, plural: str, lang: str = None, n=1):
        """
        Plural translations
        """
        if lang is None:
            lang = self.context_lang.get()

        if lang not in self.translations:
            if n == 1:
                return singular
            return plural

        translator = self.translations[lang]
        return translator.ngettext(singular, plural, n)