def insertRuleset(self, ruleset, domain):
		'''增加一个robots.txt规则集'''
		cur = self.conn.cursor()
		cur.execute("SELECT did FROM Domains WHERE domain=?", (domain,))
		did = cur.fetchone()[0]
		cur.execute("INSERT INTO Rulesets VALUES (NULL,?,?)",(did, ruleset))
		# 写入到文件
		self.conn.commit()
def _apply_mask(y_true, sample_weight, masked_tokens, dtype):
  if sample_weight is None:
    sample_weight = tf.ones_like(y_true, dtype)
  else:
    sample_weight = tf.cast(sample_weight, dtype)
  for token in masked_tokens:
    mask = tf.cast(tf.not_equal(y_true, token), dtype)
    sample_weight = sample_weight * mask
  return sample_weight