I want to copy role assignments from one folder and set it to other folder

I am basically creating a subfolder and I want that folder to have same permission as its sibling

I tried

Folder sourceFolder = oWeb.GetFolderByServerRelativeUrl("Affaires/Test Affaire/Mails"); ctx.Load(sourceFolder); ctx.ExecuteQuery(); Folder destinationFolder = folder.Folders.Add("Demo");   destinationFolder.ListItemAllFields.BreakRoleInheritance(false, false); RoleAssignmentCollection roleAssignments = sourceFolder.ListItemAllFields.RoleAssignments; ctx.Load(roleAssignments); ctx.ExecuteQuery(); foreach (RoleAssignment item in roleAssignments)         {         //not sure what to do here!          destinationFolder.ListItemAllFields.RoleAssignments.Add(item.PrincipalId, item.RoleDefinitionBindings);          }