def queueLogin(self, username, password):
        """
        Login: send the username, send the password, and
        set retrieval mode to binary
        """
        FTPClientBasic.queueLogin(self, username, password)
        d = self.queueStringCommand('TYPE I', public=0)
        # If something goes wrong, call fail
        d.addErrback(self.fail)
        # But also swallow the error, so we don't cause spurious errors
        d.addErrback(lambda x: None)

        Login: send the username, send the password, and
        set retrieval mode to binary
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/ftp.py