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ex005typehints

README.md

Introduction

Here I am just experimenting with the examples from chapter 8 in Fluent Python 2nd edition by Luciano Ramelho. Luciano Ramelhos examples can be found on github.

In chapter 8 of Ramelhos books one reads: "They [type hints] are also the main focus of Chapter 15 [...]".

Installing Requirments

See Setting Up a Virtual Environmen

Notes About Code Samples

Make sure you are in directory ex005typehints:

(.venv) PS C:\Temp\python\ex005typehints>

To check type safty do something like:

(.venv) PS C:\Temp\python\ex005typehints> mypy .\boundary.py
boundary.py:44: error: Argument 1 to "concat_cars" has incompatible type "list[Bicycle]"; expected "list[Car]"  [arg-type]
Found 1 error in 1 file (checked 1 source file)

mypy can also be run on a complete project like mypy my_source_folder. In ex005typehints it can be done like shown below.

(.venv) PS C:\Temp\python\ex005typehints> mypy .

Puzzles

I puzzles me that mypy does not complain about type error in method 'test_parse_token_error'.

(.venv) PS C:\Temp\python\ex005typehints> mypy .\test_main.py
main.py:26: error: Argument 1 to "parse_token" has incompatible type "Animal"; expected "str"  [arg-type]
Found 1 error in 1 file (checked 1 source file)