Increase code coverage for dijkstra algorithm (#10695)

* Increase code coverage for dijkstra algorithm

* Add missing code coverage

Refactor to pass mypy

* Fix missing code coverage

* Remove code changes, keep doctest

* Remove ALL of the code changes

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

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

* Update dijkstra_algorithm.py

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Co-authored-by: Christian Clauss <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>