def METHOD_NAME(self, ctype, plist=[], prefix=1):
    """Returns a file-like object for writing the body of the message.
    The content-type is set to the provided ctype, and the optional
    parameter, plist, provides additional parameters for the
    content-type declaration.  The optional argument prefix determines
    where the header is inserted; 0 means append at the end, 1 means
    insert at the start. The default is to insert at the start.
    """
    for name, value in plist:
        ctype = ctype + ';\n %s=\"%s\"' % (name, value)
    self.addheader("Content-Type", ctype, prefix=prefix)
    self.flushheaders()
    self._fp.write("\n")
    return self._fp