'Handle a RETR command.
@type i: L{bytes}
@param i: A 1-based message index.
@rtype: L{Deferred}
@return: A deferred which triggers after the response to the RETR
command has been issued.'

def do_RETR(self, i):

    return self._sendMessageContent(i, (lambda fp: fp), (lambda size: ('%d' % (size,))))
