Add missing python version 3.7 on test matrix

.github/workflows/test.yml

@@ -26,7 +26,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11",]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11",]
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps:

src/pyink/ink.py

@@ -3,17 +3,24 @@
 This is a separate module for easier patch management.
 """
 
+import sys
 from typing import (
     Collection,
     List,
-    Literal,
     Optional,
     Sequence,
     Set,
     Tuple,
     Union,
     Iterator,
 )
+
+
+if sys.version_info < (3, 8):
+    from typing_extensions import Literal
+else:
+    from typing import Literal
+
 from blib2to3.pgen2.token import ASYNC, NEWLINE, STRING
 from blib2to3.pytree import type_repr
 from pyink.mode import Quote

src/pyink/linegen.py

@@ -5,7 +5,12 @@
 from dataclasses import replace
 from enum import Enum, auto
 from functools import partial, wraps
-from typing import Collection, Iterator, List, Literal, Optional, Set, Union, cast
+from typing import Collection, Iterator, List, Optional, Set, Union, cast
+
+if sys.version_info < (3, 8):
+    from typing_extensions import Final, Literal
+else:
+    from typing import Final, Literal
 
 from pyink.brackets import (
     COMMA_PRIORITY,

src/pyink/mode.py

@@ -9,13 +9,13 @@
 from enum import Enum, auto
 from hashlib import sha256
 from operator import attrgetter
-from typing import Dict, Literal, Set
+from typing import Dict, Set
 from warnings import warn
 
 if sys.version_info < (3, 8):
-    from typing_extensions import Final
+    from typing_extensions import Final, Literal
 else:
-    from typing import Final
+    from typing import Final, Literal
 
 from pyink.const import DEFAULT_LINE_LENGTH