def update(self, role_sid=values.unset,<EOL>last_consumed_message_index=values.unset):
data = values.of({'<STR_LIT>': role_sid, '<STR_LIT>': last_consumed_message_index, })<EOL>payload = self._version.update(<EOL>'<STR_LIT:POST>',<EOL>self._uri,<EOL>data=data,<EOL>)<EOL>return MemberInstance(<EOL>self._version,<EOL>payload,<EOL>service_sid=self._solution['<STR_LIT>'],<EOL>channel_sid=self._solution['<STR_LIT>'],<EOL>sid=self._solution['<STR_LIT>'],<EOL>)<EOL>
Update the MemberInstance

:param unicode role_sid: The Role assigned to this member.
:param unicode last_consumed_message_index: An Integer representing index of the last Message this Member has read within this Channel

:returns: Updated MemberInstance
:rtype: twilio.rest.chat.v1.service.channel.member.MemberInstance