Introduce style enforcement (#61)

.flake

@@ -0,0 +1,5 @@
+[flake8]
+ignore = E203, E266, E501, W503, F403, F401, W291
+max-line-length = 120
+max-complexity = 18
+select = B,C,E,F,W,T4,B9

.pre-commit-config.yaml

@@ -0,0 +1,13 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: 20.8b1
+    hooks:
+      - id: black
+        language_version: python3.6
+        args: [--line-length=120] # this should be in pyproject.toml not sure why its not picked up
+  -   repo: https://gitlab.com/pycqa/flake8
+      rev: 3.8.4
+      hooks:
+      - id: flake8
+        additional_dependencies: [flake8-typing-imports==1.9.0]
+        args: ['--config=.flake']

pyprojet.toml

@@ -0,0 +1,17 @@
+[tool.black]
+line-length = 120
+target-version = ['py36']
+exclude = '''
+/(
+    \.eggs
+  | \.git
+  | \.hg
+  | \.mypy_cache
+  | \.tox
+  | \.venv
+  | _build
+  | buck-out
+  | build
+  | dist
+)/
+'''