Q:

How to program without type safety

Java is a hard typed language, and exchanging to Python I fell a little hard to get along with no type safety.
So, can any one help me good practices and concepts to program without type safety. 

Do I need to verify on every getter and setter if the value isinstance of the desired type?
How would I use POO without type safety?
How I can encapsulate my objects without type safety?

A:

you should not type check usually. let types free. Forget about type-safety. All code in python are a kind of generic programming.
Object-oriented programming is not combined with type safety.
Python doesn't support encapsulation of instance variable or private function. But sensible pythonista uses _ prefix for private variable or function.

Instead, unit-testing will help you.
In my favorite, nosetests and watchdog are great tools.
nosetest runs all *_test.py files in your project.
watchmedo in watchdog will watch file change and does specific command.
usually I use these two tools like
$ watchmedo shell-command --patterns="*.py" --recursive --wait --command="nosetest -sv"

This one-liner runs unit-test automatically every update in *.py file.
All your code modification will be monitored.

