def open(self, host = None, port = None):
        self.host = None        # For compatibility with parent class
        self.port = None
        self.sock = None
        self.file = None
        self.process = subprocess.Popen(self.command,
            stdin=subprocess.PIPE, stdout=subprocess.PIPE,
            shell=True, close_fds=True)
        self.writefile = self.process.stdin
        self.readfile = self.process.stdout
Make sure only a few fields accept third option ("combine").
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/imaplib.py/IMAP4_stream.open--crossover with--dataset/ETHPy150Open swcarpentry/amy/workshops/test/test_event.py/TestEventMerging.test_form_invalid_values