Please create and comment the code in python. Thank you

5. Consider a bot at position (0, 0). Given a sequence of its moves, judge if this bot makes a circle, which means it moves back to the original place. The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L(Left), u (Up) and D (down). You must right a function to that verifies if the bot makes a circle. The output should be true or false representing whether the bot makes a circle