def clear_subjects
      model_properties = properties

      (model_properties - model_properties.key | relationships).each do |subject|
        next unless subject.loaded?(self)
        remove_instance_variable(subject.instance_variable_name)
      end
    end
def clear_subjects
      model_properties = properties

      (model_properties - model_properties.key | relationships).each do |subject|
        next unless subject.loaded?(self)
        remove_instance_variable(subject.instance_variable_name)
      end
    end
Remove all the ivars for properties and relationships

 @return [undefined]

 @api private