'Removes one or more instances from the specified instance group,
but does not delete those instances.
Scopes needed - one of the following:
* https://www.googleapis.com/auth/cloud-platform
* https://www.googleapis.com/auth/compute
:param  instancegroup:  The Instance Group where you are
removng instances.
:type   instancegroup: :class:``GCEInstanceGroup``
:param  node_list: List of nodes to add.
:type   node_list: ``list`` of :class:`Node` or ``list`` of
:class:`GCENode`
:return:  Return True if successful.
:rtype: ``bool``'

def remove_instances(self, node_list):

    return self.driver.ex_instancegroup_remove_instances(instancegroup=self, node_list=node_list)
