# File lib/dragonfly/model/attachment_class_methods.rb, line 125
        def evaluate_storage_options(model, attachment)
          storage_options_specs.inject({}) do |opts, spec|
            options = case spec
            when Proc then model.instance_exec(attachment, &spec)
            when Symbol
              meth = model.method(spec)
              (1 === meth.arity) ? meth.call(attachment) : meth.call
            else spec
            end
            opts.merge!(options)
            opts
          end
        end