TypeError: 'NoneType' object is not iterable :smtplib

Question

    def sendmail(self, from_addr, to_addrs, msg='hello', mail_options=[],rcpt_options=[]):
            self.ehlo_or_helo_if_needed()
            esmtp_opts = []
            if self.does_esmtp:
                    # Hmmm? what's this? -ddm
                    # self.esmtp_features['7bit']=""
                    if self.has_extn('size'):
                                esmtp_opts.append("size=%d" % len(msg))
                    for option in mail_options:
                            esmtp_opts.append(option)

            (code, resp) = self.mail(from_addr, esmtp_opts)
            if code != 250:
                self.rset()
                #raise SMTPSenderRefused(code, resp, from_addr)
            senderrs = {}
            if isinstance(to_addrs, basestring):
                to_addrs = [to_addrs]
            for each in to_addrs:
                (code, resp) = self.rcpt(each, rcpt_options)
                if (code != 250) and (code != 251):
                    senderrs[each] = (code, resp)
            if len(senderrs) == len(to_addrs):
                # the server refused all our recipients
                self.rset()
                #raise SMTPRecipientsRefused(senderrs)
            (code, resp) = self.data(msg)
            if code != 250:
                self.rset()
                #raise SMTPDataError(code, resp)
            #if we got here then somebody got our mail
            return senderrs

I am trying to build my own smtplib.I am getting TypeError: 'NoneType' object is not iterable when i try
(code, resp) = self.data(msg)

self.data() is defined as- I am using self.data() to put the message to the server.

    def data(self, msg):
            self.putcmd("data")
            (code, repl) = self.getreply()
            if self.debuglevel > 0:
                    print>>stderr, "data:", (code, repl)
            if code != 354:
                    #raise SMTPDataError(code, repl)
                    print "Err"
            else:
                    q = quotedata(msg)
                    if q[-2:] != CRLF:
                            q = q + CRLF
                    q = q + "." + CRLF
                    self.send(q)
                    (code, msg) = self.getreply()
                    if self.debuglevel > 0:
                            print>>stderr, "data:", (code, msg)
                    return (code, msg)

Answer 1

We can't tell from the code that you have posted what self.data() is doing, but it is clear from your error that it is returning None . If you try to unpack None, you get this:

>>> (code, resp) = None
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not iterable

Posting the code for self.data() might help.

Update after extra code posted:

The code (code, repl) = self.getreply() could also be unpacking None [note: there are two instances of this in self.data() ]. Is the exception raised in self.data() or in sendmail() ?

Also

if code != 354:
            #raise SMTPDataError(code, repl)
            print "Err"
else:
    ...

If you get code 354, you have commented out the raise and the function now returns None. That might also be the problem.