module RuboCop::Cop::EndlessMethodRewriter

def arguments(node, missing = '')
  node.arguments.any? ? node.arguments.source : missing
end

def correct_to_multiline(corrector, node)
  replacement = <<~RUBY.strip
    def #{node.method_name}#{arguments(node)}
      #{node.body.source}
    end
  RUBY
  corrector.replace(node, replacement)
end