code: func (a Associations) AssociationsAfterCreatable() []AssociationAfterCreatable {
  	var after []AssociationAfterCreatable
  	for i := range a {
  		if _, ok := a[i].(AssociationAfterCreatable); ok {
  			after = append(after, a[i].(AssociationAfterCreatable))
  		}
  	}
  	return after
  }
docs: // AssociationsAfterCreatable returns all associations that implement AssociationAfterCreatable
  // interface. Has Many and Has One associations are examples of this implementation.