ActionMailer::Base::LateAttachmentsProxy Ruby on Rails 5.1.2 Class ActionMailer::Base::LateAttachmentsProxy < SimpleDelegator actionmailer/lib/action_mailer/base.rb Methods # []= I inline Instance Public methods []=(_name, _content) Link Source: show | on GitHub # File actionmailer/lib/action_mailer/base.rb, line 714 def []=(_name, _content); _raise_error end inline() Link Source: show | on GitHub # File actionmailer/lib/action_mailer/base.rb, line 713 def inline; _raise_error end