default_content_for.rb

def default_content_for(name, content = nil, options = {}, &block)
  if name.is_a? Hash
    name.each { |k, v| content_for(k, v) unless content_for?(k) }
  elsif content || block_given?
    content_for(name, content, options, &block) unless content_for?(name)
  else
    raise(ArgumentError, 'expected a second argument or block for the default content')
  end
end