BREAK: drop Python 3.7 support

.pre-commit-config.yaml

@@ -43,7 +43,7 @@ repos:
     hooks:
       - id: nbqa-pyupgrade
         args:
-          - --py37-plus
+          - --py38-plus
       - id: nbqa-ruff
         args:
           - --fix
@@ -112,7 +112,7 @@ repos:
     hooks:
       - id: pyupgrade
         args:
-          - --py37-plus
+          - --py38-plus
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: v0.0.292

docs/conf.py

@@ -1,22 +1,17 @@
 from __future__ import annotations
 
+import contextlib
 import os
 import shutil
 import subprocess
 import sys
+from importlib.metadata import PackageNotFoundError
+from importlib.metadata import version as get_package_version
 
 import requests
 from pybtex.plugin import register_plugin
 
-if sys.version_info < (3, 8):
-    from importlib_metadata import PackageNotFoundError
-    from importlib_metadata import version as get_package_version
-else:
-    from importlib.metadata import PackageNotFoundError
-    from importlib.metadata import version as get_package_version
-
 sys.path.insert(0, os.path.abspath("."))
-import contextlib
 
 from _relink_references import relink_references
 from _unsrt_et_al import MyStyle

pyproject.toml

@@ -17,7 +17,6 @@ classifiers = [
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
-    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python",
@@ -31,13 +30,12 @@ dependencies = [
     "cloudpickle",
     "sympy >=1.10", # module sympy.printing.numpy and array expressions with shape kwarg
     "tensorwaves[jax]",
-    'typing-extensions; python_version <"3.8.0"',
 ]
 description = "Symbolic expressions for Dalitz-Plot Decomposition"
 dynamic = ["version"]
 license = {text = "GPLv3 or later"}
 name = "ampform-dpd"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 
 [project.optional-dependencies]
 dev = [
@@ -62,7 +60,6 @@ doc = [
     "sphinxcontrib-bibtex",
     "tensorwaves[phsp]",
     "tqdm",
-    'importlib-metadata; python_version <"3.8.0"',
 ]
 format = [
     "black",
@@ -77,7 +74,6 @@ jupyter = [
     "jupyterlab-lsp",
     "jupyterlab-myst",
     "python-lsp-server[rope]",
-    'ypy-websocket <0.8.3; python_version <"3.8.0"',
 ]
 lint = [
     "ruff",
@@ -103,7 +99,6 @@ test = [
     "pytest >=6.0", # pyproject.toml
     "pytest-cov",
     "pytest-xdist",
-    'nbmake <1.3; python_version <"3.8.0"',
 ]
 tf = [
     "tensorwaves[tf]",
@@ -152,7 +147,6 @@ preview = true
 target-version = [
     "py310",
     "py311",
-    "py37",
     "py38",
     "py39",
 ]
@@ -253,7 +247,7 @@ extend-select = [
     "YTT",
 ]
 ignore = [
-    "B028", # missing explicit stacklevel keyword
+    "B028",
     "C408",
     "D101",
     "D102",
@@ -266,7 +260,7 @@ ignore = [
     "D416",
     "E501",
     "ISC003",
-    "PLR0913", # sympy class
+    "PLR0913",
     "S301",
     "SIM108",
 ]
@@ -275,7 +269,7 @@ src = [
     "src",
     "tests",
 ]
-target-version = "py37"
+target-version = "py38"
 task-tags = ["cspell"]
 
 [tool.ruff.pep8-naming]

src/ampform_dpd/__init__.py

@@ -1,9 +1,9 @@
 # cspell:ignore msigma
 from __future__ import annotations
 
-import sys
 from functools import lru_cache
 from itertools import product
+from typing import Literal, Protocol
 
 import sympy as sp
 from ampform.sympy import PoolSum
@@ -13,6 +13,7 @@
 from sympy.physics.quantum.spin import CG, WignerD
 from sympy.physics.quantum.spin import Rotation as Wigner
 
+from ampform_dpd.angles import formulate_scattering_angle, formulate_zeta_angle
 from ampform_dpd.decay import (
     IsobarNode,
     LSCoupling,
@@ -23,13 +24,6 @@
 )
 from ampform_dpd.spin import create_spin_range
 
-from .angles import formulate_scattering_angle, formulate_zeta_angle
-
-if sys.version_info < (3, 8):
-    from typing_extensions import Literal, Protocol
-else:
-    from typing import Literal, Protocol
-
 
 @frozen
 class AmplitudeModel: