Initial Python 3.7 drop

.flake8

@@ -58,7 +58,7 @@ ignore =
     PT004,
     PT011,
     PT012
-min-version = 3.7.0
+min-version = 3.8.0
 max-complexity = 12
 per-file-ignores =
     qutebrowser/api/hook.py : N801

.github/workflows/ci.yml

@@ -128,10 +128,10 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          ### PyQt 5.15.2 (Python 3.7)
+          ### PyQt 5.15.2 (Python 3.8)
           - testenv: py37-pyqt5152
             os: ubuntu-20.04
-            python: "3.7"
+            python: "3.8"
           ### PyQt 5.15 (Python 3.10, with coverage)
           # FIXME:qt6
           # - testenv: py310-pyqt515-cov
@@ -141,10 +141,10 @@ jobs:
           - testenv: py311-pyqt515
             os: ubuntu-20.04
             python: "3.11"
-          ### PyQt 6.2 (Python 3.7)
+          ### PyQt 6.2 (Python 3.8)
           - testenv: py37-pyqt62
             os: ubuntu-20.04
-            python: "3.7"
+            python: "3.8"
           ### PyQt 6.3 (Python 3.8)
           - testenv: py38-pyqt63
             os: ubuntu-20.04

.github/workflows/recompile-requirements.yml

@@ -21,10 +21,6 @@ jobs:
       - uses: actions/checkout@v3
         with:
           persist-credentials: false
-      - name: Set up Python 3.7
-        uses: actions/setup-python@v4
-        with:
-          python-version: '3.7'
       - name: Set up Python 3.8
         uses: actions/setup-python@v4
         with:

.mypy.ini

@@ -1,5 +1,5 @@
 [mypy]
-python_version = 3.7
+python_version = 3.8
 
 ### --strict
 warn_unused_configs = True

.pylintrc

@@ -20,7 +20,7 @@ load-plugins=qute_pylint.config,
              pylint.extensions.dunder
 
 persistent=n
-py-version=3.7
+py-version=3.8
 
 [MESSAGES CONTROL]
 enable=all
@@ -52,6 +52,7 @@ disable=locally-disabled,
         too-few-public-methods,
         import-outside-toplevel,
         consider-using-f-string,
+        consider-using-assignment-expr,
         logging-fstring-interpolation,
         raise-missing-from,
         consider-using-tuple,

README.asciidoc

@@ -82,7 +82,7 @@ Requirements
 
 The following software and libraries are required to run qutebrowser:
 
-* https://www.python.org/[Python] 3.7 or newer
+* https://www.python.org/[Python] 3.8 or newer
 * https://www.qt.io/[Qt], either 6.2.0 or newer, or 5.15.0 or newer, with the following modules:
   - QtCore / qtbase
   - QtQuick (part of qtbase or qtdeclarative in some distributions)
@@ -103,7 +103,7 @@ websites and using it for transmission of sensitive data._
 * https://palletsprojects.com/p/jinja/[jinja2]
 * https://github.com/yaml/pyyaml[PyYAML]
 
-On older Python versions (3.7/3.8), the following backports are also required:
+On Python 3.8, the following backport is also required:
 
 * https://importlib-resources.readthedocs.io/[importlib_resources]
 
@@ -119,10 +119,6 @@ The following libraries are optional:
   QtWebEngine backend.
 * On Windows, https://pypi.python.org/pypi/colorama/[colorama] for colored log
   output.
-* https://importlib-metadata.readthedocs.io/[importlib_metadata] on Python 3.7,
-  to improve QtWebEngine version detection when PyQtWebEngine is
-  installed via pip (thus, this dependency usually isn't relevant for
-  packagers).
 * https://asciidoc.org/[asciidoc] to generate the documentation for the `:help`
   command, when using the git repository (rather than a release).
 

doc/changelog.asciidoc

@@ -57,9 +57,9 @@ Added
 Removed
 ~~~~~~~
 
-- Support for Python 3.6 is dropped, as it's been
+- Python 3.8.0 or newer is now required.
-  https://discuss.python.org/t/python-3-6-rides-into-the-sunset/12964[end-of-life upstream]
+  - Support for Python 3.6 and 3.7 is dropped, as they both reached
-  since December 2021. Python 3.7.0 or newer is now required.
+    their [end of life] in December 2021 and June 2023, respectively.
 - Support for Qt/PyQt before 5.15.0 and QtWebEngine before 5.15.2 are now
   dropped, as older Qt versions are
   https://endoflife.date/qt[end-of-life upstream] since mid/late 2020

doc/contributing.asciidoc

@@ -111,9 +111,9 @@ unittests and several linters/checkers.
 Currently, the following tox environments are available:
 
 * Tests using https://www.pytest.org[pytest]:
-  - `py37`, `py38`, ...: Run pytest for python 3.7/3.8/... with the system-wide PyQt.
+  - `py38`, `py39`, ...: Run pytest for python 3.8/3.9/... with the system-wide PyQt.
-  - `py37-pyqt512`, ..., `py37-pyqt515`: Run pytest with the given PyQt version (`py37-*` also works).
+  - `py38-pyqt515`, ..., `py38-pyqt65`: Run pytest with the given PyQt version (`py39-*` etc. also works).
-  - `py37-pyqt515-cov`: Run with coverage support (other Python/PyQt versions work too).
+  - `py38-pyqt515-cov`: Run with coverage support (other Python/PyQt versions work too).
 * `flake8`: Run various linting checks via https://pypi.python.org/pypi/flake8[flake8].
 * `vulture`: Run https://pypi.python.org/pypi/vulture[vulture] to find
   unused code portions.
@@ -171,16 +171,16 @@ Examples:
 
 ----
 # run only pytest tests which failed in last run:
-tox -e py37 -- --lf
+tox -e py38 -- --lf
 
 # run only the end2end feature tests:
-tox -e py37 -- tests/end2end/features
+tox -e py38 -- tests/end2end/features
 
 # run everything with undo in the generated name, based on the scenario text
-tox -e py37 -- tests/end2end/features/test_tabs_bdd.py -k undo
+tox -e py38 -- tests/end2end/features/test_tabs_bdd.py -k undo
 
 # run coverage test for specific file (updates htmlcov/index.html)
-tox -e py37-cov -- tests/unit/browser/test_webelem.py
+tox -e py38-cov -- tests/unit/browser/test_webelem.py
 ----
 
 Specifying the backend for tests

doc/install.asciidoc

@@ -38,7 +38,7 @@ version (Qt 5.7, based on a Chromium from March 2016). Furthermore, it packages
 Ubuntu 16.04 doesn't come with an up-to-date engine (a new enough QtWebKit, or
 QtWebEngine) and also comes with Python 3.5.
 
-You should be able to install a newer Python (3.7+) using the
+You should be able to install a newer Python (3.8+) using the
 https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa[deadsnakes PPA] or
 https://github.com/pyenv/pyenv[pyenv], and then proceed to
 <<tox,install qutebrowser in a virtualenv>>. However, this is currently untested. If you
@@ -452,7 +452,7 @@ This installs all needed Python dependencies in a `.venv` subfolder
 This comes with an up-to-date Qt/PyQt including a pre-compiled QtWebEngine
 binary, but has a few caveats:
 
-- Make sure your `python3` is Python 3.7 or newer, otherwise you'll get a "No
+- Make sure your `python3` is Python 3.8 or newer, otherwise you'll get a "No
   matching distribution found" error and/or qutebrowser will not run.
 - It only works on 64-bit x86 systems, with other architectures you'll get the
   same error.

misc/requirements/requirements-mypy.txt-raw

@@ -7,4 +7,3 @@ types-PyYAML
 
 # So stubs are available even on newer Python versions
 importlib_resources
-importlib_metadata

misc/requirements/requirements-pylint.txt

@@ -8,7 +8,7 @@ cryptography==41.0.1
 dill==0.3.6
 github3.py==4.0.1
 idna==3.4
-isort==5.11.5
+isort==5.12.0
 lazy-object-proxy==1.9.0
 mccabe==0.7.0
 pefile==2023.2.7
@@ -20,10 +20,7 @@ python-dateutil==2.8.2
 ./scripts/dev/pylint_checkers
 requests==2.31.0
 six==1.16.0
-tomli==2.0.1
 tomlkit==0.11.8
-typed-ast==1.5.4 ; python_version<"3.8"
-typing_extensions==4.6.3
 uritemplate==4.1.1
 # urllib3==2.0.3
 wrapt==1.15.0

misc/requirements/requirements-qutebrowser.txt-raw

@@ -20,10 +20,4 @@ Pygments  # For :view-source --pygments or on QtWebKit
 colorama  # Colored log output on Windows
 adblock  # Improved adblocking
 
-# Optional, only relevant when installing PyQt5/PyQtWebEngine via pip.
+#@ markers: importlib-resources python_version=="3.8.*"
-importlib-metadata  # Determining PyQt version
-typing_extensions  # from importlib-metadata
-
-#@ markers: importlib-resources python_version=="3.7.*" or python_version=="3.8.*"
-#@ markers: importlib-metadata python_version=="3.7.*"
-#@ markers: typing_extensions python_version<"3.8"

misc/requirements/requirements-tests.txt

@@ -8,17 +8,15 @@ charset-normalizer==3.1.0
 cheroot==10.0.0
 click==8.1.3
 coverage==7.2.7
-exceptiongroup==1.1.1
 execnet==1.9.0
 filelock==3.12.2
-Flask==2.3.2 ; python_version>="3.8"
+Flask==2.3.2
 hunter==3.6.1
 hypothesis==6.79.3
 idna==3.4
-importlib-metadata==6.7.0
 iniconfig==2.0.0
 itsdangerous==2.1.2
-jaraco.functools==3.8.0 ; python_version>="3.8"
+jaraco.functools==3.8.0
 # Jinja2==3.1.2
 Mako==1.2.4
 manhole==1.8.0
@@ -49,12 +47,7 @@ sortedcontainers==2.4.0
 soupsieve==2.4.1
 tldextract==3.4.4
 toml==0.10.2
-tomli==2.0.1
 typing_extensions==4.6.3
 urllib3==2.0.3
 vulture==2.7
-Werkzeug==2.3.6 ; python_version>="3.8"
+Werkzeug==2.3.6
-zipp==3.15.0
-Flask==2.2.5 ; python_version=="3.7.*"
-Werkzeug==2.2.3 ; python_version=="3.7.*"
-jaraco.functools<3.8.0 ; python_version=="3.7.*"

misc/requirements/requirements-tests.txt-raw

@@ -32,10 +32,3 @@ pytest-xdist
 tldextract
 
 #@ ignore: Jinja2, MarkupSafe, colorama
-# Python 3.7
-#@ markers: Flask python_version>="3.8"
-#@ add: Flask==2.2.5 ; python_version=="3.7.*"
-#@ markers: Werkzeug python_version>="3.8"
-#@ add: Werkzeug==2.2.3 ; python_version=="3.7.*"
-#@ markers: jaraco.functools python_version>="3.8"
-#@ add: jaraco.functools<3.8.0 ; python_version=="3.7.*"

qutebrowser/commands/command.py

@@ -403,21 +403,12 @@ class Command:
             raise TypeError("{}: Legacy tuple type annotation!".format(
                 self.name))
 
-        try:
+        origin = typing.get_origin(typ)
-            origin = typing.get_origin(typ)  # type: ignore[attr-defined]
-        except AttributeError:
-            # typing.get_origin was added in Python 3.8
-            origin = getattr(typ, '__origin__', None)
-
         if origin is Union:
-            try:
+            types = list(typing.get_args(typ))
-                types = list(typing.get_args(typ))  # type: ignore[attr-defined]
-            except AttributeError:
-                # typing.get_args was added in Python 3.8
-                types = list(typ.__args__)
-
             if param.default is not inspect.Parameter.empty:
                 types.append(type(param.default))
+
             choices = self.get_arg_info(param).choices
             value = argparser.multitype_conv(param, types, value,
                                              str_choices=choices)

qutebrowser/misc/checkpyver.py

@@ -43,11 +43,11 @@ except ImportError:  # pragma: no cover
 # to stderr.
 def check_python_version():
     """Check if correct python version is run."""
-    if sys.hexversion < 0x03070000:
+    if sys.hexversion < 0x03080000:
         # We don't use .format() and print_function here just in case someone
         # still has < 2.6 installed.
         version_str = '.'.join(map(str, sys.version_info[:3]))
-        text = ("At least Python 3.7 is required to run qutebrowser, but " +
+        text = ("At least Python 3.8 is required to run qutebrowser, but " +
                 "it's running with " + version_str + ".\n")
 
         show_errors = '--no-err-windows' not in sys.argv

qutebrowser/misc/earlyinit.py

@@ -19,7 +19,7 @@
 
 """Things which need to be done really early (e.g. before importing Qt).
 
-At this point we can be sure we have all python 3.7 features available.
+At this point we can be sure we have all python 3.8 features available.
 """
 
 try:

qutebrowser/utils/resources.py

@@ -27,7 +27,7 @@ import pathlib
 from typing import Iterator, Iterable, Union
 
 
-# We cannot use the stdlib version on 3.7-3.8 because we need the files() API.
+# We cannot use the stdlib version on 3.8 because we need the files() API.
 if sys.version_info >= (3, 11):  # pragma: no cover
     # https://github.com/python/cpython/issues/90276
     import importlib.resources as importlib_resources

qutebrowser/utils/version.py

@@ -33,6 +33,7 @@ import datetime
 import getpass
 import functools
 import dataclasses
+import importlib.metadata
 from typing import (Mapping, Optional, Sequence, Tuple, ClassVar, Dict, cast,
                     TYPE_CHECKING)
 
@@ -520,19 +521,9 @@ def _get_pyqt_webengine_qt_version() -> Optional[str]:
     PyQtWebEngine 5.15.4 renamed it to PyQtWebEngine-Qt5...:
     https://www.riverbankcomputing.com/pipermail/pyqt/2021-March/043699.html
 
-    Here, we try to use importlib.metadata or its backport (optional dependency) to
+    Here, we try to use importlib.metadata to figure out that version number.
-    figure out that version number. If PyQtWebEngine is installed via pip, this will
+    If PyQtWebEngine is installed via pip, this will give us an accurate answer.
-    give us an accurate answer.
     """
-    try:
-        import importlib.metadata as importlib_metadata  # type: ignore[import]
-    except ImportError:
-        try:
-            import importlib_metadata
-        except ImportError:
-            log.misc.debug("Neither importlib.metadata nor backport available")
-            return None
-
     names = (
         ['PyQt6-WebEngine-Qt6']
         if machinery.IS_QT6 else
@@ -541,8 +532,8 @@ def _get_pyqt_webengine_qt_version() -> Optional[str]:
 
     for name in names:
         try:
-            return importlib_metadata.version(name)
+            return importlib.metadata.version(name)
-        except importlib_metadata.PackageNotFoundError:
+        except importlib.metadata.PackageNotFoundError:
             log.misc.debug(f"{name} not found")
 
     return None

requirements.txt

@@ -2,14 +2,11 @@
 
 adblock==0.6.0
 colorama==0.4.6
-importlib-metadata==6.7.0 ; python_version=="3.7.*"
+importlib-resources==5.12.0 ; python_version=="3.8.*"
-importlib-resources==5.12.0 ; python_version=="3.7.*" or python_version=="3.8.*"
 Jinja2==3.1.2
 MarkupSafe==2.1.3
 Pygments==2.15.1
 PyYAML==6.0
-typing_extensions==4.6.3 ; python_version<"3.8"
-zipp==3.15.0
 # Unpinned due to recompile_requirements.py limitations
 pyobjc-core ; sys_platform=="darwin"
 pyobjc-framework-Cocoa ; sys_platform=="darwin"

scripts/dev/changelog_urls.json

@@ -23,7 +23,6 @@
   "Flask": "https://flask.palletsprojects.com/en/latest/changes/",
   "Mako": "https://docs.makotemplates.org/en/latest/changelog.html",
   "hypothesis": "https://hypothesis.readthedocs.io/en/latest/changes.html",
-  "exceptiongroup": "https://github.com/agronholm/exceptiongroup/blob/main/CHANGES.rst",
   "mypy": "https://mypy-lang.blogspot.com/",
   "types-PyYAML": "https://github.com/python/typeshed/commits/main/stubs/PyYAML",
   "pytest": "https://docs.pytest.org/en/latest/changelog.html",
@@ -84,7 +83,6 @@
   "pyinstaller": "https://pyinstaller.readthedocs.io/en/stable/CHANGES.html",
   "pyinstaller-hooks-contrib": "https://github.com/pyinstaller/pyinstaller-hooks-contrib/blob/master/CHANGELOG.rst",
   "pytest-benchmark": "https://pytest-benchmark.readthedocs.io/en/stable/changelog.html",
-  "typed-ast": "https://github.com/python/typed_ast/commits/master",
   "docutils": "https://docutils.sourceforge.io/RELEASE-NOTES.html",
   "bump2version": "https://github.com/c4urself/bump2version/blob/master/CHANGELOG.md",
   "six": "https://github.com/benjaminp/six/blob/master/CHANGES",

scripts/dev/recompile_requirements.py

@@ -144,11 +144,11 @@ def run_pip(venv_dir, *args, quiet=False, **kwargs):
     return subprocess.run([venv_python, '-m', 'pip'] + args, check=True, **kwargs)
 
 
-def init_venv(host_python, venv_dir, requirements, pre=False, pip_args=None):
+def init_venv(venv_dir, requirements, pre=False, pip_args=None):
     """Initialize a new virtualenv and install the given packages."""
     with utils.gha_group('Creating virtualenv'):
         utils.print_col('$ python3 -m venv {}'.format(venv_dir), 'blue')
-        subprocess.run([host_python, '-m', 'venv', venv_dir], check=True)
+        subprocess.run([sys.executable, '-m', 'venv', venv_dir], check=True)
 
         run_pip(venv_dir, 'install', '-U', 'pip', quiet=not utils.ON_CI)
         run_pip(venv_dir, 'install', '-U', 'setuptools', 'wheel', quiet=not utils.ON_CI)
@@ -347,17 +347,6 @@ def print_changed_files():
         print('::set-output name=diff::' + diff_table)
 
 
-def get_host_python(name):
-    """Get the Python to use for a given requirement name.
-
-    pylint installs typed_ast on < 3.8 only
-    """
-    if name == 'pylint':
-        return 'python3.7'
-    else:
-        return sys.executable
-
-
 def get_venv_python(venv_dir):
     """Get the path to Python inside a virtualenv."""
     subdir = 'Scripts' if os.name == 'nt' else 'bin'
@@ -375,14 +364,12 @@ def build_requirements(name):
     """Build a requirements file."""
     utils.print_subtitle("Building")
     filename = os.path.join(REQ_DIR, 'requirements-{}.txt-raw'.format(name))
-    host_python = get_host_python(name)
 
     with open(filename, 'r', encoding='utf-8') as f:
         comments = read_comments(f)
 
     with tempfile.TemporaryDirectory() as tmpdir:
-        init_venv(host_python=host_python,
+        init_venv(venv_dir=tmpdir,
-                  venv_dir=tmpdir,
                   requirements=filename,
                   pre=comments['pre'],
                   pip_args=comments['pip_args'])
@@ -411,14 +398,13 @@ def build_requirements(name):
 
 def test_tox():
     """Test requirements via tox."""
-    host_python = get_host_python('tox')
     req_path = os.path.join(REQ_DIR, 'requirements-tox.txt')
 
     with tempfile.TemporaryDirectory() as tmpdir:
         venv_dir = os.path.join(tmpdir, 'venv')
         tox_workdir = os.path.join(tmpdir, 'tox-workdir')
         venv_python = get_venv_python(venv_dir)
-        init_venv(host_python, venv_dir, req_path)
+        init_venv(venv_dir, req_path)
         list_proc = subprocess.run([venv_python, '-m', 'tox', '--listenvs'],
                                    check=True,
                                    stdout=subprocess.PIPE,
@@ -448,9 +434,8 @@ def test_requirements(name, outfile, *, force=False):
     with open(in_file, 'r', encoding='utf-8') as f:
         comments = read_comments(f)
 
-    host_python = get_host_python(name)
     with tempfile.TemporaryDirectory() as tmpdir:
-        init_venv(host_python, tmpdir, outfile, pip_args=comments['pip_args'])
+        init_venv(tmpdir, outfile, pip_args=comments['pip_args'])
 
 
 def cleanup_pylint_build():

setup.py

@@ -73,7 +73,7 @@ try:
         zip_safe=True,
         install_requires=['jinja2', 'PyYAML',
                           'importlib_resources>=1.1.0; python_version < "3.9"'],
-        python_requires='>=3.7',
+        python_requires='>=3.8',
         name='qutebrowser',
         version=_get_constant('version'),
         description=_get_constant('description'),
@@ -95,9 +95,10 @@ try:
             'Operating System :: MacOS',
             'Operating System :: POSIX :: BSD',
             'Programming Language :: Python :: 3',
-            'Programming Language :: Python :: 3.7',
             'Programming Language :: Python :: 3.8',
             'Programming Language :: Python :: 3.9',
+            'Programming Language :: Python :: 3.10',
+            'Programming Language :: Python :: 3.11',
             'Topic :: Internet',
             'Topic :: Internet :: WWW/HTTP',
             'Topic :: Internet :: WWW/HTTP :: Browsers',

tests/end2end/test_invocations.py

@@ -336,7 +336,7 @@ def test_command_on_start(request, quteproc_new):
     quteproc_new.wait_for_quit()
 
 
-@pytest.mark.parametrize('python', ['python2', 'python3.6'])
+@pytest.mark.parametrize('python', ['python2', 'python3.6', 'python3.7'])
 def test_launching_with_old_python(python):
     try:
         proc = subprocess.run(
@@ -346,7 +346,7 @@ def test_launching_with_old_python(python):
     except FileNotFoundError:
         pytest.skip(f"{python} not found")
     assert proc.returncode == 1
-    error = "At least Python 3.7 is required to run qutebrowser"
+    error = "At least Python 3.8 is required to run qutebrowser"
     assert proc.stderr.decode('ascii').startswith(error)
 
 

tests/unit/misc/test_checkpyver.py

@@ -28,7 +28,7 @@ import pytest
 from qutebrowser.misc import checkpyver
 
 
-TEXT = (r"At least Python 3.7 is required to run qutebrowser, but it's "
+TEXT = (r"At least Python 3.8 is required to run qutebrowser, but it's "
         r"running with \d+\.\d+\.\d+.")
 
 

tests/unit/utils/test_version.py

@@ -29,6 +29,7 @@ import logging
 import textwrap
 import datetime
 import dataclasses
+import importlib.metadata
 
 import pytest
 import hypothesis
@@ -1106,24 +1107,10 @@ class TestChromiumVersion:
         """Simulate parsing the version from ELF to fail."""
         monkeypatch.setattr(elf, 'parse_webenginecore', lambda: None)
 
-    @pytest.fixture
-    def patch_no_importlib(self, monkeypatch, stubs):
-        """Simulate missing importlib modules."""
-        import_fake = stubs.ImportFake({
-            'importlib_metadata': False,
-            'importlib.metadata': False,
-        }, monkeypatch)
-        import_fake.patch()
-
     @pytest.fixture
     def importlib_patcher(self, monkeypatch):
         """Patch the importlib module."""
         def _patch(*, qt, qt5, qt6):
-            try:
-                import importlib.metadata as importlib_metadata
-            except ImportError:
-                importlib_metadata = pytest.importorskip("importlib_metadata")
-
             def _fake_version(name):
                 if name == 'PyQtWebEngine-Qt':
                     outcome = qt
@@ -1135,10 +1122,10 @@ class TestChromiumVersion:
                     raise utils.Unreachable(name)
 
                 if outcome is None:
-                    raise importlib_metadata.PackageNotFoundError(name)
+                    raise importlib.metadata.PackageNotFoundError(name)
                 return outcome
 
-            monkeypatch.setattr(importlib_metadata, 'version', _fake_version)
+            monkeypatch.setattr(importlib.metadata, 'version', _fake_version)
 
         return _patch
 
@@ -1150,7 +1137,6 @@ class TestChromiumVersion:
     @pytest.mark.parametrize('patches, sources', [
         (['no_api'], ['ELF', 'importlib', 'PyQt', 'Qt']),
         (['no_api', 'elf_fail'], ['importlib', 'PyQt', 'Qt']),
-        (['no_api', 'elf_fail', 'no_importlib'], ['PyQt', 'Qt']),
         (['no_api', 'elf_fail', 'importlib_no_package'], ['PyQt', 'Qt']),
     ], ids=','.join)
     def test_simulated(self, request, patches, sources):

tox.ini

@@ -35,7 +35,6 @@ passenv =
 basepython =
     py: {env:PYTHON:python3}
     py3: {env:PYTHON:python3}
-    py37: {env:PYTHON:python3.7}
     py38: {env:PYTHON:python3.8}
     py39: {env:PYTHON:python3.9}
     py310: {env:PYTHON:python3.10}