'A CSV file may be malformed and lack traling commas at the end of a row.
In this case, those cells take on the value None by the CSV parser.
Make sure we handle None values appropriately.
i.e.:
header_1,header_2,header_3
val_1,val_2,val_3  <- good row
val_1,,  <- good row
val_1    <- bad row; no trailing commas to indicate empty rows'

def test_too_few_commas(self):

    result = self._cohort_students_and_upload(u'username,email,cohort\nstudent_1\xec,\nstudent_2')
    self.assertDictContainsSubset({'total': 2, 'attempted': 2, 'succeeded': 0, 'failed': 2}, result)
    self.verify_rows_in_csv([dict(zip(self.csv_header_row, ['', 'False', '0', '', '', '']))], verify_order=False)
