Fix CI and docstring.

Author: Patryk Szulczewski

.github/workflows/ci.yml

@@ -86,7 +86,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
     runs-on: "ubuntu-20.04"
     env:
       PYTHON_VER: "${{ matrix.python-version }}"