- Assigned_roles means the role designated to specific assignee for specific tasks. - It determines the assignee's responsibility. - Here Parent can assign the task to their respective childs. - For example : Here we have the hierarchy Owner-->Manager-->TeamLead-->Developers. - so according to this hierarchy Owner can assign role to manager for specific task. - similarly manager can assign roles to Teamlead and Teamlead can assign to developers. - If we try to get the assigned roles in developers for a specific task then it'll filter out and return the result. - if no developers found for that assigned role then it'll check in Teamlead to get those assigned roles. - This method of filtration to get desired result is following percolation.