## Diff of /doc/source/using_pyke/proving_goals.txt[4dca5a] .. [1c77af]  Maximize  Restore

### Switch to side-by-side view

```--- a/doc/source/using_pyke/proving_goals.txt
+++ b/doc/source/using_pyke/proving_goals.txt
@@ -83,7 +83,7 @@
>>> my_engine.prove_1_goal('bc_related0.father_son(thomas, bogus, \$depth)')
Traceback (most recent call last):
...
-    CanNotProve: Can not prove bc_related0.father_son(thomas, bogus, \$depth)
+    pyke.knowledge_engine.CanNotProve: Can not prove bc_related0.father_son(thomas, bogus, \$depth)

*some_engine*.prove_goal(goal, \*\*args)
This returns a context manager for a generator yielding 2-tuples, as
@@ -95,7 +95,7 @@
>>> with my_engine.prove_goal(
...        'bc_related0.father_son(thomas, \$son, \$depth)') as gen:
...     for vars, plan in gen:
-    ...         print vars['son'], vars['depth']
+    ...         print(vars['son'], vars['depth'])
bruce ()
david ('grand',)

@@ -106,7 +106,7 @@
...        'bc_related0.father_son(\$father, \$son, \$depth)',
...        father='thomas') as gen:
...     for vars, plan in gen:
-    ...         print vars['son'], vars['depth']
+    ...         print(vars['son'], vars['depth'])
bruce ()
david ('grand',)

@@ -129,7 +129,7 @@

>>> with my_goal.prove(my_engine, father='thomas') as gen:
...     for vars, plan in gen:
-    ...         print vars['son'], vars['depth']
+    ...         print(vars['son'], vars['depth'])
bruce ()
david ('grand',)

```