1. Create a list for each column, then create the following Dataframe : (4 Marks) 2. Create a list containing the total grade of each student (use loop: for) (5 Marks) 3. Add column 'total' to the dataframe. (3 Marks) 4. Finally, the student DD didn't attend the Midterm. Replace his/her grade by NAN value (use: np.NaN)