4 3. simple nesting + rebinding
5 4. nesting with global but no free
6 5. nesting through class
7 6. nesting plus free ref to global
8 7. nearest enclosing scope
9 8. mixed freevars and cellvars
10 9. free variable in method
12 11. unoptimized namespaces
15 14. complex definitions
16 15. scope of global statements
19 18. verify that locals() works
20 19. var is bound and free in class
21 20. interaction with trace function
22 20. eval and exec with free variables
23 21. list comprehension with local variables