--- a/assertType.m	Fri Nov 03 10:43:27 2017 +0100
+++ b/assertType.m	Fri Nov 03 10:53:15 2017 +0100
@@ -1,5 +1,11 @@
 function assertType(obj, type)
-    if ~isa(obj, type)
-        error('sbplib:assertType:wrongType', '"%s" must have type "%s", found "%s"', inputname(1), type, class(obj));
+    if ~iscell(type)
+        if ~isa(obj, type)
+            error('sbplib:assertType:wrongType', '"%s" must have type "%s", found "%s"', inputname(1), type, class(obj));
+        end
+    else
+        if ~isAnyOf(obj, type)
+            error('sbplib:assertType:wrongType', '"%s" must be one of the types %s, found "%s"', inputname(1), toString(type), class(obj));
+        end
     end
 end