Start auto-formatting using yapf

.flake8

@@ -1,31 +1,7 @@
 [flake8]
-# NOTE: The idea is to start with non-critical checks disabled
-#       so that we can activate flake8 without a huge diff
-#       upfront to already benefit from all still enabled checks,
-#       and remove issue a class at a time, potentially
-#       even multiple at once if we start using an auto-reformatter.
-# E124 closing bracket does not match visual indentation
-# E123 closing bracket does not match indentation of opening bracket's line
-# E125 continuation line with same indent as next logical line
-# E126 continuation line over-indented for hanging indent
-# E127 continuation line over-indented for visual indent
-# E128 continuation line under-indented for visual indent
-# E221 multiple spaces before operator
-# E241 multiple spaces after ','
-# E251 unexpected spaces around keyword / parameter equals
-# E501 line too long (xxx > 79 characters)
 # W503 line break before binary operator
 # W504 line break after binary operator
 ignore =
-    E124
-    E123
-    E125
-    E126
-    E127
-    E128
-    E221
-    E241
-    E251
-    E501
     W503
     W504
+max-line-length = 99

.pre-commit-config.yaml

@@ -44,3 +44,10 @@ repos:
     rev: v1.0.1
     hooks:
       - id: rst-linter
+
+    # TODO Move to https://github.com/google/yapf
+    #      after >=0.31 has been released
+  - repo: https://github.com/pre-commit/mirrors-yapf/
+    rev: v0.30.0
+    hooks:
+      - id: yapf

.style.yapf

@@ -0,0 +1,4 @@
+[style]
+based_on_style = pep8
+column_limit = 99
+split_before_arithmetic_operator = True