Add pre-commit configuration

.flake8

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+[flake8]
+max-line-length = 88
+max-complexity = 16
+# B = bugbear
+# B9 = bugbear opinionated (incl line length)
+select = E,F,W,B,B9
+# E203: whitespace before ':' (black behaviour)
+# E501: flake8 line length (covered by bugbear B950)
+# W503: line break before binary operator (black behaviour)
+# W504: line break after binary operator (black behaviour)
+ignore = E203,E501,W503,W504
+exclude =
+  ./.git
+  .eggs/

.pre-commit-config.yaml

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+default_language_version:
+  python: python3
+repos:
+  - repo: local
+    hooks:
+      # These files are most likely copier diff rejection junks; if found,
+      # review them manually, fix the problem (if needed) and remove them
+      - id: forbidden-files
+        name: forbidden files
+        entry: found forbidden files; remove them
+        language: fail
+        files: "\\.rej$"
+  - repo: https://github.com/myint/autoflake
+    rev: v2.1.1
+    hooks:
+      - id: autoflake
+        args:
+          - --expand-star-imports
+          - --ignore-init-module-imports
+          - --in-place
+          - --remove-all-unused-imports
+          - --remove-duplicate-keys
+          - --remove-unused-variables
+  - repo: https://github.com/psf/black
+    rev: 23.3.0
+    hooks:
+      - id: black
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v3.1.0
+    hooks:
+      - id: prettier
+        name: prettier (with plugin-xml)
+        additional_dependencies:
+          - "[email protected]"
+          - "@prettier/[email protected]"
+        args:
+          - --plugin=@prettier/plugin-xml
+        files: \.(css|htm|html|js|json|jsx|less|md|scss|toml|ts|xml|yaml|yml)$
+  - repo: https://github.com/pre-commit/mirrors-eslint
+    rev: v8.40.0
+    hooks:
+      - id: eslint
+        verbose: true
+        args:
+          - --color
+          - --fix
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.4.0
+    hooks:
+      - id: trailing-whitespace
+        # exclude autogenerated files
+        exclude: /README\.rst$|\.pot?$
+      - id: end-of-file-fixer
+        # exclude autogenerated files
+        exclude: /README\.rst$|\.pot?$
+      - id: debug-statements
+      - id: fix-encoding-pragma
+        args: ["--remove"]
+      - id: check-case-conflict
+      - id: check-docstring-first
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+        # exclude files where underlines are not distinguishable from merge conflicts
+        exclude: /README\.rst$|^docs/.*\.rst$
+      - id: check-symlinks
+      - id: check-xml
+      - id: mixed-line-ending
+        args: ["--fix=lf"]
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v3.4.0
+    hooks:
+      - id: pyupgrade
+        args: ["--keep-percent-format"]
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.12.0
+    hooks:
+      - id: isort
+        name: isort except __init__.py
+        args:
+          - --settings=.
+        exclude: /__init__\.py$
+  - repo: https://github.com/PyCQA/flake8
+    rev: 6.0.0
+    hooks:
+      - id: flake8
+        name: flake8
+        additional_dependencies: ["flake8-bugbear==20.1.4"]