Make backwards-compatible

There are two options suggested in
#809:

1. use TypeError to catch non-existent omit_sections kw. This will work with
master but will be less clear when we deprecate IPython 7.x in a few years.

2. use IPython version_info, which makes cleanup easier but means we won't be
able to use this feature with master IPython, only v8.

Going with #2 because it's cleaner.

Author: Ahmed Fasih

ipykernel/ipkernel.py

@@ -5,6 +5,7 @@
 from contextlib import contextmanager
 from functools import partial
 import getpass
+import re
 import signal
 import sys
 
@@ -466,13 +467,20 @@ def do_inspect(self, code, cursor_pos, detail_level=0, omit_sections=()):
         reply_content['data'] = {}
         reply_content['metadata'] = {}
         try:
-            reply_content['data'].update(
-                self.shell.object_inspect_mime(
+            if release.version_info >= (8,):
+                # `omit_sections` keyword will be available in IPython 8, see
+                # https://github.com/ipython/ipython/pull/13343
+                bundle = self.shell.object_inspect_mime(
                     name,
                     detail_level=detail_level,
                     omit_sections=omit_sections,
                 )
-            )
+            else:
+                bundle = self.shell.object_inspect_mime(
+                    name,
+                    detail_level=detail_level
+                )
+            reply_content['data'].update(bundle)
             if not self.shell.enable_html_pager:
                 reply_content['data'].pop('text/html')
             reply_content['found'] = True