'Changes the status of the specified access key from Active to Inactive
or vice versa.  This action can be used to disable a user\'s key as
part of a key rotation workflow.
If the user_name is not specified, the user_name is determined
implicitly based on the AWS Access Key ID used to sign the request.
:type access_key_id: string
:param access_key_id: The ID of the access key.
:type status: string
:param status: Either Active or Inactive.
:type user_name: string
:param user_name: The username of user (optional).'

def update_access_key(self, access_key_id, status, user_name=None):

    params = {'AccessKeyId': access_key_id, 'Status': status}
    if user_name:
        params['UserName'] = user_name
    return self.get_response('UpdateAccessKey', params)
