Modernize code and add a test

.pre-commit-config.yaml

@@ -0,0 +1,31 @@
+# See https://pre-commit.com/hooks.html for info on hooks
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v3.4.0
+    hooks:
+      - id: check-added-large-files
+      - id: check-ast
+      - id: check-case-conflict
+      - id: check-toml
+      - id: check-yaml
+      - id: debug-statements
+      - id: detect-private-key
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+
+  - repo: https://github.com/psf/black
+    rev: 19.10b0
+    hooks:
+      - id: black
+
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: 3.9.0
+    hooks:
+      - id: flake8
+        args: [--max-line-length=88]
+        language_version: python3.7
+
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.7.0
+    hooks:
+      - id: isort