diff --git a/src/ocrmypdf/_pipelines/_common.py b/src/ocrmypdf/_pipelines/_common.py
index 0044d0a4..b3b88500 100644
--- a/src/ocrmypdf/_pipelines/_common.py
+++ b/src/ocrmypdf/_pipelines/_common.py
@@ -186,7 +186,7 @@ def configure_debug_logging(
     return log_file_handler, remover
 
 
-def worker_init(max_pixels: int) -> None:
+def worker_init(max_pixels: int | None) -> None:
     """Initialize a worker thread or process."""
     # In Windows, child process will not inherit our change to this value in
     # the parent process, so ensure workers get it set. Not needed when running
diff --git a/src/ocrmypdf/api.py b/src/ocrmypdf/api.py
index 69de7fbd..7fc412ad 100644
--- a/src/ocrmypdf/api.py
+++ b/src/ocrmypdf/api.py
@@ -14,7 +14,7 @@ from collections.abc import Iterable, Sequence
 from enum import IntEnum
 from io import IOBase
 from pathlib import Path
-from typing import AnyStr, BinaryIO
+from typing import BinaryIO
 from warnings import warn
 
 import pluggy
@@ -28,7 +28,7 @@ from ocrmypdf._validation import check_options
 from ocrmypdf.cli import ArgumentParser, get_parser
 from ocrmypdf.helpers import is_iterable_notstr
 
-StrPath = Path | AnyStr
+StrPath = Path | str | bytes
 PathOrIO = BinaryIO | StrPath
 
 # Installing plugins affects the global state of the Python interpreter,
@@ -140,9 +140,9 @@ def configure_logging(
 
 def _kwargs_to_cmdline(
     *, defer_kwargs: set[str], **kwargs
-) -> tuple[list[str], dict[str, AnyStr]]:
+) -> tuple[list[str | bytes], dict[str, str | bytes]]:
     """Convert kwargs to command line arguments."""
-    cmdline = []
+    cmdline: list[str | bytes] = []
     deferred = {}
     for arg, val in kwargs.items():
         if val is None:
@@ -279,7 +279,7 @@ def ocr(  # noqa: D417
     fast_web_view: float | None = None,
     continue_on_soft_render_error: bool | None = None,
     invalidate_digital_signatures: bool | None = None,
-    plugins: Iterable[StrPath] | None = None,
+    plugins: Iterable[Path | str] | None = None,
     plugin_manager=None,
     keep_temporary_files: bool | None = None,
     progress_bar: bool | None = None,
@@ -420,7 +420,7 @@ def _pdf_to_hocr(  # noqa: D417
     continue_on_soft_render_error: bool | None = None,
     invalidate_digital_signatures: bool | None = None,
     plugin_manager=None,
-    plugins: Sequence[StrPath] | None = None,
+    plugins: Sequence[Path | str] | None = None,
     keep_temporary_files: bool | None = None,
     **kwargs,
 ):
@@ -491,7 +491,7 @@ def _hocr_to_ocr_pdf(  # noqa: D417
     color_conversion_strategy: str | None = None,
     fast_web_view: float | None = None,
     plugin_manager=None,
-    plugins: Sequence[StrPath] | None = None,
+    plugins: Sequence[Path | str] | None = None,
     **kwargs,
 ):
     """Run OCRmyPDF on a work folder and produce an output PDF.
diff --git a/src/ocrmypdf/hocrtransform/_hocr.py b/src/ocrmypdf/hocrtransform/_hocr.py
index 47a1952b..fd4dfe9b 100644
--- a/src/ocrmypdf/hocrtransform/_hocr.py
+++ b/src/ocrmypdf/hocrtransform/_hocr.py
@@ -357,7 +357,7 @@ class HocrTransform:
         line_matrix: Matrix,
         text: Text,
         fontsize: float,
-        elem: Element,
+        elem: Element | None,
         next_elem: Element | None,
         text_direction: TextDirection,
         inject_word_breaks: bool,
@@ -434,7 +434,7 @@ class HocrTransform:
                 if ocr_par is None:
                     continue
                 canvas.do.rect(
-                    ocr_par.llx, ocr_par.lly, ocr_par.width, ocr_par.height, fill=0
+                    ocr_par.llx, ocr_par.lly, ocr_par.width, ocr_par.height, fill=False
                 )
 
     def _debug_draw_line_bbox(self, canvas: Canvas, line_box: Rectangle, color=BLUE):
@@ -443,7 +443,7 @@ class HocrTransform:
             return
         with canvas.do.save_state():
             canvas.do.stroke_color(color).line_width(0.15).rect(
-                line_box.llx, line_box.lly, line_box.width, line_box.height, fill=0
+                line_box.llx, line_box.lly, line_box.width, line_box.height, fill=False
             )
 
     def _debug_draw_word_triangle(
@@ -467,7 +467,7 @@ class HocrTransform:
             return
         with canvas.do.save_state():
             canvas.do.stroke_color(color).line_width(line_width).rect(
-                box.llx, box.lly, box.width, box.height, fill=0
+                box.llx, box.lly, box.width, box.height, fill=False
             )
 
     def _debug_draw_space_bbox(
@@ -478,7 +478,7 @@ class HocrTransform:
             return
         with canvas.do.save_state():
             canvas.do.fill_color(color).line_width(line_width).rect(
-                box.llx, box.lly, box.width, box.height, fill=1
+                box.llx, box.lly, box.width, box.height, fill=True
             )
 
     def _debug_draw_baseline(
diff --git a/src/ocrmypdf/optimize.py b/src/ocrmypdf/optimize.py
index 43506dc6..c2ea7bf5 100644
--- a/src/ocrmypdf/optimize.py
+++ b/src/ocrmypdf/optimize.py
@@ -75,10 +75,15 @@ def extract_image_filter(
     """Determine if an image is extractable."""
     if image.Subtype != Name.Image:
         return None
-    if image.Length < 100:
+    if not isinstance(image.Length, int) or image.Length < 100:
         log.debug(f"xref {xref}: skipping image with small stream size")
         return None
-    if image.Width < 8 or image.Height < 8:  # Issue 732
+    if (
+        not isinstance(image.Width, int)
+        or not isinstance(image.Height, int)
+        or image.Width < 8
+        or image.Height < 8
+    ):  # Issue 732
         log.debug(f"xref {xref}: skipping image with unusually small dimensions")
         return None