explicity declaration of module

app/builders/learning_object/attachment_builder.rb

-module LearningObject
-  class AttachmentBuilder < ::Builder
+class LearningObject::AttachmentBuilder < ::Builder
 
-    ##disable method
-    # build attachments with id's is out of scope.
-    def self.build(objects = [])
-      raise NotImplementedError, 'LearningObject::AttachmentBuilder#build is out of scope.'
-    end
+  ##disable method
+  # build attachments with id's is out of scope.
+  def self.build(objects = [])
+    raise NotImplementedError, 'LearningObject::AttachmentBuilder#build is out of scope.'
+  end
 
-    def self.build_from_orientdb(args = {})
-      args['retrieve_link'] = args.delete('retrieveLink')
-      args['mime_type'] = args.delete('mimeType')
-      build_from_cache args do
-        ::LearningObject::Attachment.new(args)
-      end
+  def self.build_from_orientdb(args = {})
+    args['retrieve_link'] = args.delete('retrieveLink')
+    args['mime_type'] = args.delete('mimeType')
+    build_from_cache args do
+      ::LearningObject::Attachment.new(args)
     end
+  end
 
-    private
-
-    def self.build_from_cache(args={})
-      object = nil
+  private
 
-      unless args.nil? || !block_given?
-        # cache object when build
-        object = Rails.cache.fetch(cache_key(args['id'], args['link']), expires_in: 12.hours) { yield }
-      end
+  def self.build_from_cache(args={})
+    object = nil
 
-      object
+    unless args.nil? || !block_given?
+      # cache object when build
+      object = Rails.cache.fetch(cache_key(args['id'], args['link']), expires_in: 12.hours) { yield }
     end
 
-    def self.permitted_args(args={})
-      permitted = [:id, :name, :link, :retrieve_link, :description, :format, :mime_type, :size]
-      args.delete_if do |key, value|
-        !permitted.include? key.to_sym
-      end
-    end
+    object
+  end
 
+  def self.permitted_args(args={})
+    permitted = [:id, :name, :link, :retrieve_link, :description, :format, :mime_type, :size]
+    args.delete_if do |key, value|
+      !permitted.include? key.to_sym
+    end
   end
+
 end
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