mjo/clan/clan_operator.py: swap isinstance() for category check

Amazingly, this also fails, still ONLY while doctesting.

diff --git a/mjo/clan/clan_operator.py b/mjo/clan/clan_operator.py
index 28f134f87f27399f2cde43e141c1382ae91c2a21..82c06395a65938eea5c3f8bb4623f782cb7ce415 100644 (file)
--- a/mjo/clan/clan_operator.py
+++ b/mjo/clan/clan_operator.py
@@ -30,12 +30,12 @@ class ClanOperator(Map):
     """
 
     def __init__(self, domain, codomain, mat):
-        from mjo.clan.clan import Clan
+        from mjo.clan.clan import Clans
 
-        if not isinstance(domain, Clan):
-            raise TypeError('domain must be a clan')
-        if not isinstance(codomain, Clan):
-            raise TypeError('codomain must be a clan')
+        if not domain in Clans:
+            raise TypeError("domain must be a clan")
+        if not codomain in Clans:
+            raise TypeError("codomain must be a clan")
 
         F = domain.base_ring()
         if not (F == codomain.base_ring()):