def publish_tx(self, txdata):
        url = self.url_stem % "%s/publish_tx"
        req = urllib2.Request(url, txdata,
                              {'Content-Type': 'application/json'})
        f = urllib2.urlopen(req)
        reply = f.read()
        f.close()
        if reply[0] == 'E' or (len(reply) != 64):
            raise Exception(reply)
        else:
            return reply
dataset/ETHPy150Open chromaway/ngcccbase/ngcccbase/services/chroma.py/ChromaBlockchainState.publish_tx/swapped operands of `%`