Since feedparser messes with Python’s internals by assigning
to __code__ it needs to import SGMLParseError too. It also
expects SGMLParseError, which was turned into AssertionError by
https://github.com/python/cpython/commit/e34bbfd61f405eef89e8aa50672b0b25022de320

--- feedparser-6.0.10/feedparser/sgml.py.orig	2023-03-18 09:24:50.976316932 +0100
+++ feedparser-6.0.10/feedparser/sgml.py	2023-03-18 09:26:32.971928811 +0100
@@ -28,6 +28,7 @@
 import re
 
 import sgmllib
+from sgmllib import SGMLParseError
 
 __all__ = [
     'sgmllib',
@@ -41,6 +42,7 @@
     'shorttagopen',
     'starttagopen',
     'endbracket',
+    'SGMLParseError',
 ]
 
 # sgmllib defines a number of module-level regular expressions that are
--- feedparser-6.0.10/feedparser/html.py.orig	2023-03-18 09:32:03.647114745 +0100
+++ feedparser-6.0.10/feedparser/html.py	2023-03-18 09:46:05.021142671 +0100
@@ -349,7 +349,7 @@
 
         try:
             return sgmllib.SGMLParser.parse_declaration(self, i)
-        except sgmllib.SGMLParseError:
+        except AssertionError:
             # Escape the doctype declaration and continue parsing.
             self.handle_data('<')
             return i+1
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<tr><td><span title='2022-05-25 09:27:25 +0200'>2022-05-25</span></td><td><a href='/guix/commit/etc/release-manifest.scm?id=dab819d5c4c55609efae098c8e3c2f2757c34e5b'>Move (gnu platform) and (gnu platforms ...) to guix/.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2022-05-22 15:15:33 +0200'>2022-05-22</span></td><td><a href='/guix/commit/etc/release-manifest.scm?id=dd970122ddf3679482f658f73dd68307496c6215'>ci: Do not rely on hardcoded cross-targets lists.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
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<tr><td><span title='2020-04-14 16:01:05 +0200'>2020-04-14</span></td><td><a href='/guix/commit/etc/release-manifest.scm?id=bab1f340b35078dcfd3cbac67ad56393b53bb46b'>maint: Ensure substitutes are available for '%default-xorg-modules'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-04-14 16:01:05 +0200'>2020-04-14</span></td><td><a href='/guix/commit/etc/release-manifest.scm?id=8e8d984fd6db77bb5c1bec66369e5e99470d416f'>maint: Actually check for the availablility of system packages.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-04-08 13:05:34 +0200'>2020-04-08</span></td><td><a href='/guix/commit/etc/release-manifest.scm?id=b1f56712c00a39c36ddd87fa42e3a19a28a75ffd'>maint: Adjust release manifest for Guile 3.0 switch.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
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