'prefix is ignored if add_to_http_hdrs is true.'

def startbody(self, ctype=None, plist=[], prefix=1, add_to_http_hdrs=0, content_type=1):

    if (content_type and ctype):
        for (name, value) in plist:
            ctype = (ctype + (';\r\n    %s=%s' % (name, value)))
        self.addheader('Content-Type', ctype, prefix=prefix, add_to_http_hdrs=add_to_http_hdrs)
    self.flushheaders()
    if (not add_to_http_hdrs):
        self._fp.write('\r\n')
    self._first_part = True
    return self._fp
