BANDIT reports assert. Replace assert with raise.

Assert used but it can be removed from optimized code.
The check looks like it is required. So raise an AssertionFailure.

Author: rouilj

roundup/admin.py

@@ -1228,7 +1228,8 @@ class colon_separated(csv.excel):
                 # for a safe upper bound of field length we add
                 # difference between CSV len and sum of all field lengths
                 d = sum ([len(x) for x in exp]) - lensum
-                assert (d > 0)
+                if not d > 0:
+                    raise AssertionError("Bad assertion d > 0")
                 for p in propnames:
                     ll = len(repr_export(node[p])) + d
                     if ll > max_len: