'Write data for a subitem of this control to a MimeWriter.'

def _write_mime_data(self, mw, name, value):

    mw2 = mw.nextpart()
    mw2.addheader('Content-Disposition', ('form-data;    name="%s"' % name), 1)
    f = mw2.startbody(prefix=0)
    f.write(value)
