code: func (a Associations) AssociationsBeforeCreatable() []AssociationBeforeCreatable {
  	var before []AssociationBeforeCreatable
  	for i := range a {
  		if _, ok := a[i].(AssociationBeforeCreatable); ok {
  			before = append(before, a[i].(AssociationBeforeCreatable))
  		}
  	}
  	return before
  }
docs: // AssociationsBeforeCreatable returns all associations that implement AssociationBeforeCreatable
  // interface. Belongs To association is an example of this implementation.