class ActiveAdmin::ResourceCollection

def [](klass)

Finds a resource based on the resource name, the resource class, or the base class. 
def [](klass)
  if match = @resources[klass]
    match
  elsif match = real_resources.detect{ |r| [r.resource_name.to_s, r.resource_class.to_s].include? klass.to_s }
    match
  elsif klass.respond_to? :base_class
    real_resources.detect{ |r| r.resource_class.to_s == klass.base_class.to_s }
  end
end