'Updates name and/or path of the specified group.
:type group_name: string
:param group_name: The name of the new group
:type new_group_name: string
:param new_group_name: If provided, the name of the group will be
changed to this name.
:type new_path: string
:param new_path: If provided, the path of the group will be
changed to this path.'

def update_group(self, group_name, new_group_name=None, new_path=None):

    params = {'GroupName': group_name}
    if new_group_name:
        params['NewGroupName'] = new_group_name
    if new_path:
        params['NewPath'] = new_path
    return self.get_response('UpdateGroup', params)
