Update to python 3.9.

- Some hand editing
- `pyupgrade --py39-plus`

Author: schwehr

pyproject.toml

@@ -39,7 +39,7 @@ line-length = 88
 indent-width = 4
 
 # Assume Python 3.9
-target-version = "py37"
+target-version = "py39"
 
 [tool.ruff.lint]
 # Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
@@ -67,7 +67,6 @@ skip-magic-trailing-comma = false
 line-ending = "auto"
 
 
-
 [tool.pylint.MASTER]
 load-plugins=[
     "pylint_per_file_ignores",

setup.cfg

@@ -16,15 +16,14 @@ keywords = gis, geospatial, geographic, shapefile, shapefiles
 classifiers =
     Development Status :: 5 - Production/Stable
     Programming Language :: Python
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Topic :: Scientific/Engineering :: GIS
     Topic :: Software Development :: Libraries
     Topic :: Software Development :: Libraries :: Python Modules
 
 [options]
 py_modules = shapefile
-python_requires = >=2.7
+python_requires = >=3.9
 
 [bdist_wheel]
 universal=1