Set up code formatting tools

- auto-format code with:
  + autoflake => * remove unused imports and variables
                 * remove duplicate dict keys
                 * expand star imports
  + black => enforce an uncompromising code style
  + isort => enforce a consistent import style
             compliant with Google's Python style guide
- add nox session "format" to run these tools

pyproject.toml

@@ -32,6 +32,10 @@ python = "^3.9"
 
 [tool.poetry.group.dev.dependencies]
 
+# Code formatters
+autoflake = "^2.3"
+black = "^24.8"
+isort = "^5.13"
 
 
 [tool.poetry.urls]
@@ -40,6 +44,57 @@ python = "^3.9"
 
 
 
+[tool.autoflake]
+# Source: https://github.com/PyCQA/autoflake#configuration
+
+in-place = true
+recursive = true
+expand-star-imports = true
+remove-all-unused-imports = true
+ignore-init-module-imports = true  # modifies "remove-all-unused-imports"
+remove-duplicate-keys = true
+remove-unused-variables = true
+
+
+
+[tool.black]
+# Source: https://black.readthedocs.io/en/stable/usage_and_configuration/the_basics.html
+
+line-length = 88
+target-version = ["py312", "py311", "py310", "py39"]
+
+
+
+[tool.isort]
+# Source: https://pycqa.github.io/isort/docs/configuration/options.html
+
+known_first_party = ["lalib"]
+
+atomic = true
+case_sensitive = true
+combine_star = true
+force_alphabetical_sort_within_sections = true
+lines_after_imports = 2
+remove_redundant_aliases = true
+
+# Comply with black's style => Instead of: 'profile = "black"'
+# Source: https://pycqa.github.io/isort/docs/configuration/profiles.html
+ensure_newline_before_comments = true
+force_grid_wrap = 0
+include_trailing_comma = true
+line_length = 88
+multi_line_output = 3
+split_on_trailing_comma = true
+use_parentheses = true
+
+# Comply with Google's Python style guide
+# => All imports go on a single line (with some exceptions)
+# Source: https://google.github.io/styleguide/pyguide.html#313-imports-formatting
+force_single_line = true
+single_line_exclusions = ["collections.abc", "typing"]
+
+
+
 [build-system]
 
 requires = ["poetry-core"]