Taken from Gentoo, which adapted
https://github.com/agronholm/typeguard/commit/e0db07a777d5a481eaba6162354adf32286ce21b

diff --git a/src/typeguard/__init__.py b/src/typeguard/__init__.py
index 5684d63..27fa30b 100644
--- a/src/typeguard/__init__.py
+++ b/src/typeguard/__init__.py
@@ -61,22 +61,25 @@ except ImportError:
     from typing import _ForwardRef as ForwardRef
     evaluate_forwardref = ForwardRef._eval_type
 
-if sys.version_info >= (3, 10):
-    from typing import is_typeddict
-else:
-    _typed_dict_meta_types = ()
-    if sys.version_info >= (3, 8):
-        from typing import _TypedDictMeta
-        _typed_dict_meta_types += (_TypedDictMeta,)
+try:
+    from typing_extensions import is_typeddict
+except ImportError:
+    if sys.version_info >= (3, 10):
+        from typing import is_typeddict
+    else:
+        _typed_dict_meta_types = ()
+        if sys.version_info >= (3, 8):
+            from typing import _TypedDictMeta
+            _typed_dict_meta_types += (_TypedDictMeta,)
 
-    try:
-        from typing_extensions import _TypedDictMeta
-        _typed_dict_meta_types += (_TypedDictMeta,)
-    except ImportError:
-        pass
+        try:
+            from typing_extensions import _TypedDictMeta
+            _typed_dict_meta_types += (_TypedDictMeta,)
+        except ImportError:
+            pass
 
-    def is_typeddict(tp) -> bool:
-        return isinstance(tp, _typed_dict_meta_types)
+        def is_typeddict(tp) -> bool:
+            return isinstance(tp, _typed_dict_meta_types)
 
 
 if TYPE_CHECKING:
f3b10dad17f157378'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/guix-shell-export-manifest.sh'>
<input type='hidden' name='id' value='fa2404ff1ffcf4f522c7400f3b10dad17f157378'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>root</a>/<a href='/guix/log/tests?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>tests</a>/<a href='/guix/log/tests/guix-shell-export-manifest.sh?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378'>guix-shell-export-manifest.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-shell-export-manifest.sh?id=fa2404ff1ffcf4f522c7400f3b10dad17f157378&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-06-16 23:57:40 +0200'>2022-06-16</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=925a57c5d04553ff6c514867348e7d3c5c22ca66'>shell: Fix '--export-manifest' for cached profiles and when '-p' is used.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://issues.guix.gnu.org/55521&gt;.

* guix/scripts/shell.scm (export-manifest): When computing 'manifest',
honor the 'profile key.
* tests/guix-shell-export-manifest.sh: Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-06-01 22:22:19 +0200'>2022-06-01</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=2acc83daa5a3dd1b4ed3f8c32ecadf1313e6fd18'>shell: '--export-manifest -D x -D y' generates a valid manifest.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/shell.scm (manifest-&gt;code*): Add missing 'list' in
generated 'concatenate-manifests' call.
* tests/guix-shell-export-manifest.sh: Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-04-08 18:14:35 +0200'>2022-04-08</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=20691c70cf2c5a61af7f906b65d57a524ecfc4f3'>tests: 'guix shell --export-manifest' test no longer needs networking.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-shell-export-manifest.sh: Use '--with-input' rather than
'--with-latest' as the latter would crash in the absence of network
access.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-04-04 22:58:04 +0200'>2022-04-04</span></td><td><a href='/guix/commit/tests/guix-shell-export-manifest.sh?id=c42b7baf13c7633b4512e94da7445299c57b247d'>shell: Add '--export-manifest'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/shell.scm (show-help, %options): Add '--export-manifest'.
(manifest-entry-version-prefix, manifest-&gt;code*)
(export-manifest): New procedures.
(guix-shell): Honor '--export-manifest'.
* tests/guix-shell-export-manifest.sh: New file.
* Makefile.am (SH_TESTS): Add it.
* doc/guix.texi (Invoking guix shell): Document '--export-manifest'.
(Invoking guix environment): Link to it.
(Invoking guix pack): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>