def writeSomeData(self, data):
        """
        Send as much of C{data} as possible.  Also send any pending file
        descriptors.
        """
        # Make it a programming error to send more file descriptors than you
        # send regular bytes.  Otherwise, due to the limitation mentioned
        # below, we could end up with file descriptors left, but no bytes to
        # send with them, therefore no way to send those file descriptors.
        if len(self._sendmsgQueue) > len(data):
            return error.FileDescriptorOverrun()

        # If there are file descriptors to send, try sending them first, using
        # a little bit of data from the stream-oriented write buffer too.  It
        # is not possible to send a file descriptor without sending some
        # regular data.
        index = 0
        try:
            while index < len(self._sendmsgQueue):
                fd = self._sendmsgQueue[index]
                try:
                    untilConcludes(
                        sendmsg.sendmsg, self.socket, data[index:index+1],
                        _ancillaryDescriptor(fd))
                except socket.error as se:
                    if se.args[0] in (EWOULDBLOCK, ENOBUFS):
                        return index
                    else:
                        return main.CONNECTION_LOST
                else:
                    index += 1
        finally:
            del self._sendmsgQueue[:index]

        # Hand the remaining data to the base implementation.  Avoid slicing in
        # favor of a buffer, in case that happens to be any faster.
        limitedData = lazyByteSlice(data, index)
        result = self._writeSomeDataBase.writeSomeData(self, limitedData)
        try:
            return index + result
        except TypeError:
            return result

        Send as much of C{data} as possible.  Also send any pending file
        descriptors.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/unix.py