Remove false positive example

Author: gjbex

source-code/typing/README.md

@@ -1,40 +1,42 @@
-# Typing Python 3.5 introducd optional type annotation for functions, and
-that functionality was extended in Python 3.6.
+# Typing
+
+Python 3.5 introducd optional type annotation for functions, and that
+functionality was extended in Python 3.6.
 
 The `mypy` static type checker can use this annotation to detect type errors.
 
 Type checking can be done using [mypy](http://mypy-lang.org/index.html).
 
+
 ## What is it?
+
 1. `mypy.ini`: mypy configuration file.
 1. `correct.py`: code that has type annotations, and no type errors.
-1. `incorrect_01.py`: code that has type annotations, and passes a string to
-   a function that expects an `int`.
+1. `incorrect_01.py`: code that has type annotations, and passes a string to a
+   function that expects an `int`.
 1. `incorrect_02.py`: code that has type annotations, and the result of a
    function that returns an `int` is assigned to a `str` variable.
 1. `incorrect_03.py`: code that has type annotations, and the result of a
-   function that returns an `int`, assigns it to a variable that is later
-   used as a `str`.
+   function that returns an `int`, assigns it to a variable that is later used
+   as a `str`.
 1. `dict_correct.py`: code that counts the words in a text read from standard
    input.
-1. `dict_incorrect.py`: code that counts the words in a text read from
-   standard input.  The counts are subsequently normalized to `float`, which
-   is a type error.
-1. `people_incorrect.py`: code that defines a `People` class, stores some in
-   a list with mistakes.
+1. `dict_incorrect.py`: code that counts the words in a text read from standard
+   input.  The counts are subsequently normalized to `float`, which is a type
+   error.
+1. `people_incorrect.py`: code that defines a `People` class, stores some in a
+   list with mistakes.
 1. `duck_typing.py`: example code illustrating duck typing.
-1. `duck_typing_incorrect.py`: example code illustrating duck typing, but
-   with an error.
+1. `duck_typing_incorrect.py`: example code illustrating duck typing, but with
+   an error.
 1. `typed_duck_typing.py`: example code illustrating duck typing using type
    hints.
 1. `typed_duck_typing_clean.py`: example code illustrating duck typing using
    type hints with a factory function.
 1. `typed_duck_typing_incorrect.py`: example code illustrating duck typing
    using type hints with an error.
-1. `typed_duck_typing_false_positive.py`: example code illustrating duck
-   typing using type hints for which mypy 0.910 generates a false positive.
-1. `numpy_typing.py`: illustration of a script using both numpy and
-   matplotlib with type hints.
+1. `numpy_typing.py`: illustration of a script using both numpy and matplotlib
+   with type hints.
 1. `classes.py`: illustration of using type hints with a user-defined class.
-1. `classes_incorrect.py`: illustration of using type hints with a
-   user-defined class with errors.
+1. `classes_incorrect.py`: illustration of using type hints with a user-defined
+   class with errors.

source-code/typing/typed_duck_typing.py

@@ -32,9 +32,5 @@ def sound_repeater(sound_maker: SoundMaker, nr_repeats: int) -> None:
     arg_parser.add_argument('--n', type=int, default=1,
                             help='number of sounds to make')
     options = arg_parser.parse_args()
-    sound_maker: SoundMaker
-    if options.type == 'duck':
-        sound_maker = Duck()
-    else:
-        sound_maker = AlarmClock()
+    sound_maker: SoundMaker = Duck() if options.type == 'duck' else AlarmClock()
     sound_repeater(sound_maker, options.n)