diff --git a/IPython/terminal/ipapp.py b/IPython/terminal/ipapp.py
index df4648b..6280bce 100755
--- a/IPython/terminal/ipapp.py
+++ b/IPython/terminal/ipapp.py
@@ -156,7 +156,7 @@ frontend_flags['i'] = (
 flags.update(frontend_flags)
 
 aliases = dict(base_aliases)
-aliases.update(shell_aliases)
+aliases.update(shell_aliases)  # type: ignore[arg-type]
 
 #-----------------------------------------------------------------------------
 # Main classes and functions
@@ -180,7 +180,7 @@ class LocateIPythonApp(BaseIPythonApplication):
 class TerminalIPythonApp(BaseIPythonApplication, InteractiveShellApp):
     name = u'ipython'
     description = usage.cl_usage
-    crash_handler_class = IPAppCrashHandler
+    crash_handler_class = IPAppCrashHandler  # typing: ignore[assignment]
     examples = _examples
 
     flags = flags
diff --git a/IPython/terminal/shortcuts/__init__.py b/IPython/terminal/shortcuts/__init__.py
index c4af137..bc0c95c 100644
--- a/IPython/terminal/shortcuts/__init__.py
+++ b/IPython/terminal/shortcuts/__init__.py
@@ -163,11 +163,11 @@ def create_ipython_shortcuts(shell, for_all_platforms: bool = False):
             return _preceding_text_cache[pattern]
 
         if callable(pattern):
-
             def _preceding_text():
                 app = get_app()
                 before_cursor = app.current_buffer.document.current_line_before_cursor
-                return bool(pattern(before_cursor))
+                # mypy can't infer if(callable): https://github.com/python/mypy/issues/3603
+                return bool(pattern(before_cursor))  # type: ignore[operator]
 
         else:
             m = re.compile(pattern)
diff --git a/IPython/terminal/shortcuts/auto_suggest.py b/IPython/terminal/shortcuts/auto_suggest.py
index 8c699d8..f623f8e 100644
--- a/IPython/terminal/shortcuts/auto_suggest.py
+++ b/IPython/terminal/shortcuts/auto_suggest.py
@@ -1,7 +1,7 @@
 import re
 import tokenize
 from io import StringIO
-from typing import Callable, List, Optional, Union
+from typing import Callable, List, Optional, Union, Generator, Tuple
 
 from prompt_toolkit.buffer import Buffer
 from prompt_toolkit.key_binding import KeyPressEvent
@@ -19,7 +19,11 @@ def _get_query(document: Document):
 
 
 class NavigableAutoSuggestFromHistory(AutoSuggestFromHistory):
-    """ """
+    """
+    A subclass of AutoSuggestFromHistory that allow navigation to next/previous
+    suggestion from history. To do so it remembers the current position, but it
+    state need to carefully be cleared on the right events.
+    """
 
     def __init__(
         self,
@@ -56,7 +60,24 @@ class NavigableAutoSuggestFromHistory(AutoSuggestFromHistory):
 
     def _find_match(
         self, text: str, skip_lines: float, history: History, previous: bool
-    ):
+    ) -> Generator[Tuple[str, float], None, None]:
+        """
+        text: str
+
+        skip_lines: float
+            float is used as the base value is +inf
+
+        Yields
+        ------
+        Tuple with:
+        str:
+            current suggestion.
+        float:
+            will actually yield only ints, which is passed back via skip_lines,
+            which may be a +inf (float)
+
+
+        """
         line_number = -1
         for string in reversed(list(history.get_strings())):
             for line in reversed(string.splitlines()):