create_extension_module

# File activerecord/lib/active_record/associations.rb, line 1246
        def create_extension_module(association_id, extension)
          extension_module_name = "#{self.to_s}#{association_id.to_s.camelize}AssociationExtension"

          silence_warnings do
            Object.const_set(extension_module_name, Module.new(&extension))
          end
          
          extension_module_name.constantize
        end