Doctest Error Correction of mirror_formulae.py (#9782)

* Python mirror_formulae.py is added to the repository

* Changes done after reading readme.md

* Changes for running doctest on all platforms

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Change 2 for Doctests

* Changes for doctest 2

* updating DIRECTORY.md

* Doctest whitespace error rectification to mirror_formulae.py

* updating DIRECTORY.md

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

Author: 4 people

DIRECTORY.md

@@ -469,6 +469,7 @@
   * [Djb2](hashes/djb2.py)
   * [Elf](hashes/elf.py)
   * [Enigma Machine](hashes/enigma_machine.py)
+  * [Fletcher16](hashes/fletcher16.py)
   * [Hamming Code](hashes/hamming_code.py)
   * [Luhn](hashes/luhn.py)
   * [Md5](hashes/md5.py)

physics/mirror_formulae.py

@@ -66,7 +66,7 @@ def focal_length(distance_of_object: float, distance_of_image: float) -> float:
     >>> from math import isclose
     >>> isclose(focal_length(9.5, 6.7), 3.929012346)
     True
-    >>> focal_length(0, 20)
+    >>> focal_length(0, 20)  # doctest: +NORMALIZE_WHITESPACE
     Traceback (most recent call last):
         ...
     ValueError: Invalid inputs. Enter non zero values with respect
@@ -89,7 +89,7 @@ def object_distance(focal_length: float, distance_of_image: float) -> float:
     >>> from math import isclose
     >>> isclose(object_distance(10.5, 11.7), 102.375)
     True
-    >>> object_distance(90, 0)
+    >>> object_distance(90, 0)  # doctest: +NORMALIZE_WHITESPACE
     Traceback (most recent call last):
         ...
     ValueError: Invalid inputs. Enter non zero values with respect
@@ -112,7 +112,7 @@ def image_distance(focal_length: float, distance_of_object: float) -> float:
     >>> from math import isclose
     >>> isclose(image_distance(1.5, 6.7), 1.932692308)
     True
-    >>> image_distance(0, 0)
+    >>> image_distance(0, 0)  # doctest: +NORMALIZE_WHITESPACE
     Traceback (most recent call last):
         ...
     ValueError: Invalid inputs. Enter non zero values with respect