Support for the Ruby 2.4 series has ended. See here for reference.
ChannelBase
# File rss/maker/0.9.rb, line 26 def to_feed(rss) channel = Rss::Channel.new setup_values(channel) _not_set_required_variables = not_set_required_variables if _not_set_required_variables.empty? rss.channel = channel set_parent(channel, rss) setup_items(rss) setup_image(rss) setup_textinput(rss) setup_other_elements(rss, channel) rss else raise NotSetError.new("maker.channel", _not_set_required_variables) end end