example.rb

def get_artist
  Artist.find params[:artist_id]
end

def get_label
  Label.find params[:label_id]
end

  
def parent_object
  if params[:artist_id]
    @parent = get_artist
    @mode = 'artist'
  elsif params[:label_id]
    @parent = get_label
    @mode = 'label'
  else
    raise StandardError, "Unable to get parent object."
  end
end