Where is message defined on HTTParty::Response?

[ajtoo]

Maybe this is a silly question, but until lately, I haven't thought much of it. When I try to mock the #message method for an instance_double, it comes back with HTTParty::Response class does not implement the instance method: message. If I introspect the method, there doesn't seem to be a source location, and I can't find a documented definition. Is this just a native, non ruby method from somewhere?

[12] pry(main)> res.method(:message).source_location
=> nil
[13] pry(main)> res.message
=> "Unauthorized"
[14] pry(main)> res.method(:message)
=> #<Method: HTTParty::Response#message(*)>
[15] pry(main)> res.method(:message).owner
=> HTTParty::Response