'Remove instances from GCEInstanceGroupManager and destroy
the instance
Scopes needed - one of the following:
* https://www.googleapis.com/auth/cloud-platform
* https://www.googleapis.com/auth/compute
:param  manager:  Required. The name of the managed instance group. The
name must be 1-63 characters long, and comply with
RFC1035.
:type   manager: ``str`` or :class: `GCEInstanceGroupManager`
:param  node_list:  list of Node objects to delete.
:type   node_list: ``list`` of :class:`Node`
:return:  True if successful
:rtype: ``bool``'

def ex_instancegroupmanager_delete_instances(self, manager, node_list):

    request = ('/zones/%s/instanceGroupManagers/%s/deleteInstances' % (manager.zone.name, manager.name))
    request_data = {'instances': [x.extra['selfLink'] for x in node_list]}
    self.connection.request(request, method='POST', data=request_data).object
    return True
