[Nitro] ERROR: undefined local variable or method `attributes' for YAML::Stream:Class

[Trans]

If you are using the brand spanking new release of Facets (2.2.0) it
is because #attributes changed to #instance_attributes to prevent name
clashes with other libs. I've sent George a bundle with fixes, but
he'll need to apply it and probably do some touch up.

The new version also switches from using #class_extension and
ClassMethods hack to using the new definition of #is, which will
automatically extend a Self sub-module. Eg.

  module Foo
    module Self
      def q; "q"; end
    end
  end

  class X
    is Foo
  end

  X.q #=> "q"

T.