Method to check if any Attachment in Sharepoint Document Set is checked out

public string IsAttachmentCheckedOut(int itemID, int myListID)

        {

            string ErrorMsg = string.Empty;

            Guid lguid = new Guid(myListID);

            SPList mlist = SPContext.Current.Web.Lists[lguid];

            SPFolder mfolder = mlist.GetItemById(itemID).Folder;

            foreach (SPFile file in mfolder.Files)

            {

                if (file.CheckOutType != SPFile.SPCheckOutType.None)

                {

                    string currentUser = SPContext.Current.Web.CurrentUser.Name;

                    if (file.CheckedOutByUser.Name.ToLower().Equals(currentUser.ToLower()))

                    {

                        ErrorMsg += "The Attachment, '" + file.Name + "' is Checked Out by You.\\r\\n";

                    }

                    else

                    {

                        ErrorMsg += "The Attachment, '" + file.Name + "' is Checked Out by the User, '" + file.CheckedOutByUser.Name.ToUpper() + "'.\\r\\n";

                    }

                }

            }

            return ErrorMsg;

        }