# File lib/dragonfly/active_model_extensions/attachment_class_methods.rb, line 129
        def evaluate_storage_opts(model, attachment)
          storage_opts_specs.inject({}) do |opts, spec|
            options = case spec
            when Proc then model.instance_exec(attachment, &spec)
            when Symbol then model.send(spec)
            else spec
            end
            opts.merge!(options)
            opts
          end
        end