'Soft delete the specified instance.
A soft-deleted instance doesn\'t allocate any resources anymore, but is
still available as a database entry. The counter action :func:`restore`
uses the database entry to create a new instance based on that.
:param nova.objects.instance.Instance instance:
The instance to soft-delete.
:return: None'

def soft_delete(self, instance):

    raise NotImplementedError()
