def remove_comments(self, criteria):
     return remove_rows("com", criteria, self._connection)
 def remove_submissions(self, criteria):
     return remove_rows("su", criteria, self._connection)
 def remove_assignments(self, criteria):
     return remove_rows("as", criteria, self._connection)
 def remove_coursestudents(self, criteria):
     return remove_rows("cs", criteria, self._connection)
 def remove_students(self, criteria):
     return remove_rows("st", criteria, self._connection)
 def remove_instructors(self, criteria):
     return remove_rows("in", criteria, self._connection)