diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b3b88f1..7dc6738 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -41,6 +41,6 @@ repos:
     rev: v1.15.0
     hooks:
     -   id: mypy
-        additional_dependencies: [types-setuptools, types-requests, settngs>=0.10.4]
+        additional_dependencies: [types-setuptools, types-requests, settngs>=0.10.4, pillow>=9.1.0]
 ci:
     skip: [mypy]
diff --git a/comicapi/filenamelexer.py b/comicapi/filenamelexer.py
index 62cd880..8f1e893 100644
--- a/comicapi/filenamelexer.py
+++ b/comicapi/filenamelexer.py
@@ -382,7 +382,7 @@ def lex_number(lex: Lexer) -> LexerFunc | None:
     return lex_filename
 
 
-def lex_issue_number(lex: Lexer) -> Callable[[Lexer], Callable | None] | None:  # type: ignore[type-arg]
+def lex_issue_number(lex: Lexer) -> LexerFunc:
     # Only called when lex.input[lex.start] == "#"
     original_start = lex.pos
     lex.accept_run(str.isalpha)
diff --git a/comicapi/merge.py b/comicapi/merge.py
index 3fa8fbe..df73750 100644
--- a/comicapi/merge.py
+++ b/comicapi/merge.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 import dataclasses
 from collections.abc import Collection
 from enum import auto
-from typing import Any
+from typing import Any, Callable
 
 from comicapi.utils import DefaultDict, StrEnum, norm_fold
 
@@ -54,7 +54,7 @@ def overlay(old: Any, new: Any) -> Any:
     return new
 
 
-attribute = DefaultDict(
+attribute: DefaultDict[Mode, Callable[[Any, Any], Any]] = DefaultDict(
     {
         Mode.OVERLAY: overlay,
         Mode.ADD_MISSING: lambda old, new: overlay(new, old),
@@ -63,7 +63,7 @@ attribute = DefaultDict(
 )
 
 
-lists = DefaultDict(
+lists: DefaultDict[Mode, Callable[[Collection[Any], Collection[Any]], list[Any] | set[Any]]] = DefaultDict(
     {
         Mode.OVERLAY: merge_lists,
         Mode.ADD_MISSING: lambda old, new: merge_lists(new, old),
diff --git a/comicapi/utils.py b/comicapi/utils.py
index f3b91a9..13a4230 100644
--- a/comicapi/utils.py
+++ b/comicapi/utils.py
@@ -23,7 +23,7 @@ import pathlib
 import platform
 import sys
 import unicodedata
-from collections.abc import Iterable, Mapping
+from collections.abc import Iterable, Mapping, Sequence
 from enum import Enum, auto
 from shutil import which  # noqa: F401
 from typing import Any, Callable, TypeVar, cast
@@ -47,7 +47,7 @@ except ImportError:
 
 if sys.version_info < (3, 11):
 
-    def file_digest(fileobj, digest, /, *, _bufsize=2**18):
+    def file_digest(fileobj, digest, /, *, _bufsize=2**18):  # type: ignore[no-untyped-def]
         """Hash the contents of a file-like object. Returns a digest object.
 
         *fileobj* must be a file-like object opened for reading in binary mode.
@@ -147,12 +147,16 @@ else:
 logger = logging.getLogger(__name__)
 
 
-class DefaultDict(dict):
-    def __init__(self, *args, default: Callable[[Any], Any] | None = None) -> None:
-        super().__init__(*args)
+_KT = TypeVar("_KT")
+_VT = TypeVar("_VT")
+
+
+class DefaultDict(dict[_KT, _VT]):
+    def __init__(self, *args, default: Callable[[_KT], _VT | _KT] | None = None, **kwargs) -> None:  # type: ignore[no-untyped-def]
+        super().__init__(*args, **kwargs)
         self.default = default
 
-    def __missing__(self, key: Any) -> Any:
+    def __missing__(self, key: _KT) -> _VT | _KT:
         if self.default is None:
             return key
         return self.default(key)
@@ -170,7 +174,7 @@ def _custom_key(tup: Any) -> Any:
     lst = []
     for x in natsort.os_sort_keygen()(tup):
         ret = x
-        if len(x) > 1 and isinstance(x[1], int) and isinstance(x[0], str) and x[0] == "":
+        if isinstance(x, Sequence) and len(x) > 1 and isinstance(x[1], int) and isinstance(x[0], str) and x[0] == "":
             ret = ("a", *x[1:])
 
         lst.append(ret)
@@ -623,7 +627,7 @@ def update_publishers(new_publishers: Mapping[str, Mapping[str, str]]) -> None:
             publishers[publisher] = ImprintDict(publisher, new_publishers[publisher])
 
 
-class ImprintDict(dict):  # type: ignore
+class ImprintDict(dict[str, str]):
     """
     ImprintDict takes a publisher and a dict or mapping of lowercased
     imprint names to the proper imprint name. Retrieving a value from an
@@ -631,14 +635,14 @@ class ImprintDict(dict):  # type: ignore
     if the key does not exist the key is returned as the publisher unchanged
     """
 
-    def __init__(self, publisher: str, mapping: tuple | Mapping = (), **kwargs: dict) -> None:  # type: ignore
+    def __init__(self, publisher: str, mapping: Mapping[str, str] = {}, **kwargs) -> None:  # type: ignore[no-untyped-def]
         super().__init__(mapping, **kwargs)
         self.publisher = publisher
 
     def __missing__(self, key: str) -> None:
         return None
 
-    def __getitem__(self, k: str) -> tuple[str, str, bool]:
+    def __getitem__(self, k: str) -> tuple[str, str, bool]:  # type: ignore[override]
         item = super().__getitem__(k.casefold())
         if k.casefold() == self.publisher.casefold():
             return "", self.publisher, True
diff --git a/comictaggerlib/ctsettings/plugin_finder.py b/comictaggerlib/ctsettings/plugin_finder.py
index 9f045ae..bbb3bb0 100644
--- a/comictaggerlib/ctsettings/plugin_finder.py
+++ b/comictaggerlib/ctsettings/plugin_finder.py
@@ -10,7 +10,7 @@ import pathlib
 import platform
 import re
 import sys
-from collections.abc import Generator, Iterable
+from collections.abc import Generator, Iterable, Sequence
 from typing import Any, NamedTuple, TypeVar
 
 if sys.version_info < (3, 10):
@@ -31,7 +31,7 @@ def _custom_key(tup: Any) -> Any:
     lst = []
     for x in natsort.os_sort_keygen()(tup):
         ret = x
-        if len(x) > 1 and isinstance(x[1], int) and isinstance(x[0], str) and x[0] == "":
+        if isinstance(x, Sequence) and len(x) > 1 and isinstance(x[1], int) and isinstance(x[0], str) and x[0] == "":
             ret = ("a", *x[1:])
 
         lst.append(ret)
diff --git a/comictaggerlib/imagehasher.py b/comictaggerlib/imagehasher.py
index a629673..5ae37d0 100644
--- a/comictaggerlib/imagehasher.py
+++ b/comictaggerlib/imagehasher.py
@@ -35,7 +35,12 @@ logger = logging.getLogger(__name__)
 
 class ImageHasher:
     def __init__(
-        self, path: str | None = None, image: Image | None = None, data: bytes = b"", width: int = 8, height: int = 8
+        self,
+        path: str | None = None,
+        image: Image.Image | None = None,
+        data: bytes = b"",
+        width: int = 8,
+        height: int = 8,
     ) -> None:
         self.width = width
         self.height = height
@@ -141,6 +146,7 @@ class ImageHasher:
                 row = []
                 for x in range(width):
                     pixel = image.getpixel((x, y))
+                    assert isinstance(pixel, float)
                     row.append(pixel)
                 pixels2.append(row)
 
diff --git a/comictaggerlib/issueidentifier.py b/comictaggerlib/issueidentifier.py
index 7702c3a..913ad9d 100644
--- a/comictaggerlib/issueidentifier.py
+++ b/comictaggerlib/issueidentifier.py
@@ -132,7 +132,7 @@ class IssueIdentifier:
     def set_cover_url_callback(self, cb_func: Callable[[bytes], None]) -> None:
         self.cover_url_callback = cb_func
 
-    def calculate_hash(self, image_data: bytes = b"", image: Image = None) -> int:
+    def calculate_hash(self, image_data: bytes = b"", image: Image.Image | None = None) -> int:
         if self.image_hasher == 3:
             return ImageHasher(data=image_data, image=image).p_hash()
         if self.image_hasher == 2:
@@ -377,8 +377,8 @@ class IssueIdentifier:
 
     def _process_cover(self, name: str, image_data: bytes) -> list[tuple[str, Image.Image]]:
         assert Image
-        cover_image = Image.open(io.BytesIO(image_data))
-        images = [(name, cover_image)]
+        cover_image: Image.Image = Image.open(io.BytesIO(image_data))
+        images: list[tuple[str, Image.Image]] = [(name, cover_image)]
 
         # check the aspect ratio
         # if it's wider than it is high, it's probably a two page spread (back_cover, front_cover)
@@ -413,7 +413,7 @@ class IssueIdentifier:
 
     def _get_search_keys(self, md: GenericMetadata) -> Any:
         search_keys = SearchKeys(
-            series=md.series,
+            series=md.series or "",
             issue_number=IssueString(md.issue).as_string(),
             alternate_number=IssueString(md.alternate_number).as_string(),
             month=md.month,
diff --git a/testing/comicdata.py b/testing/comicdata.py
index 3832b11..2df4145 100644
--- a/testing/comicdata.py
+++ b/testing/comicdata.py
@@ -258,7 +258,7 @@ all_seed_imprints = {
     "Marvel": seed_imprints["Marvel"].copy(),
     "DC Comics": additional_seed_imprints["DC Comics"].copy(),
 }
-all_seed_imprints["Marvel"].update(additional_seed_imprints["Marvel"])
+all_seed_imprints["Marvel"].update(additional_seed_imprints["Marvel"].items())
 
 conflicting_seed_imprints = {"Marvel": {"test": "Never"}}