code: func (n *EvalCountCheckComputed) Eval(ctx EvalContext) (interface{}, error) {
  	if n.Resource.RawCount.Value() == unknownValue() {
  		return nil, fmt.Errorf(
  			"%s: value of 'count' cannot be computed",
  			n.Resource.Id())
  	}
  
  	return nil, nil
  }
docs: // TODO: test