I have a pandas df with columns like
StudentID | Date | TeahcerID
1 | 12/01/2020 | 3
2 | 12/01/2020 | 4
1 | 12/01/2020 | 5
1 | 12/01/2020 | 3
this is a very big dataset, we have to output the rows where the combination of all 3 columns are unique
like on the above sample dataset the last row should not be outputed since it's same as 1st one, however the second last row should be outputed even if it has same student id, because teacher id makes the row unique
output should be
StudentID | Date | TeahcerID
1 | 12/01/2020 | 3
2 | 12/01/2020 | 4
1 | 12/01/2020 | 5
