Fix(steps): Typing steps are bypassed

Useless steps where complex objects were built are not shown. I create
a typing function which is called when compute raise
NotImplementedError.

mapytex/calculus/core/__init__.py

@@ -37,10 +37,8 @@ Abstracts tools for calculs manipulations
 >>> print(t.apply_on_last_level(compute, typing))
 +
  > /
- | > *
- | | > 2
- | | > 4
- | > 4
+ | > 2
+ | > 1
  > /
  | > 3
  | > 4