class RuboCop::Cop::Rails::AfterCommitOverride

def on_class(class_node)
  seen_callback_names = {}
  each_after_commit_callback(class_node) do |node|
    callback_name = node.first_argument.value
    if seen_callback_names.key?(callback_name)
      add_offense(node, message: format(MSG, name: callback_name))
    else
      seen_callback_names[callback_name] = true
    end
  end
end