diff --git a/docs/comparing.txt b/docs/comparing.txt
index 7624be4..f9aee64 100644
--- a/docs/comparing.txt
+++ b/docs/comparing.txt
@@ -629,6 +629,12 @@ If is it important that the two values being compared are of exactly
 the same type, rather than just being equal as far as Python is
 concerned, then the strict mode of :func:`compare` should be used.
 
+.. invisible-code-block: python
+
+  # Sybil 5.0.2 above above set this to __test__, but it needs to be
+  # __main__ for Python 3.6 compatibility:
+  __name__ = '__main__'
+
 For example, these two instances will normally appear to be equal
 provided the elements within them are the same:
 
@@ -642,7 +648,7 @@ should be used:
 >>> compare(TypeA(1), TypeB(1), strict=True)
 Traceback (most recent call last):
  ...
-AssertionError: A(x=1) (<class '__test__.A'>) != B(x=1) (<class '__test__.B'>)
+AssertionError: A(x=1) (<class '__main__.A'>) != B(x=1) (<class '__main__.B'>)
 
 .. _comparison-objects: