diff --git a/src/ocrmypdf/_pipeline.py b/src/ocrmypdf/_pipeline.py
index c0333704..80d39feb 100644
--- a/src/ocrmypdf/_pipeline.py
+++ b/src/ocrmypdf/_pipeline.py
@@ -14,7 +14,7 @@ from contextlib import suppress
 from datetime import datetime, timezone
 from pathlib import Path
 from shutil import copyfileobj
-from typing import Any, Iterable, Sequence
+from typing import Any, BinaryIO, Iterable, Sequence, cast
 
 import img2pdf
 import pikepdf
@@ -575,7 +575,9 @@ def ocr_engine_hocr(input_file: Path, page_context: PageContext) -> tuple[Path,
 
 def should_visible_page_image_use_jpg(pageinfo: PageInfo) -> bool:
     # If all images were JPEGs originally, produce a JPEG as output
-    return pageinfo.images and all(im.enc == Encoding.jpeg for im in pageinfo.images)
+    return bool(pageinfo.images) and all(
+        im.enc == Encoding.jpeg for im in pageinfo.images
+    )
 
 
 def create_visible_page_jpg(image: Path, page_context: PageContext) -> Path:
@@ -892,14 +894,16 @@ def merge_sidecars(txt_files: Iterable[Path | None], context: PdfContext) -> Pat
     return output_file
 
 
-def copy_final(input_file, output_file, _context: PdfContext) -> None:
+def copy_final(
+    input_file: Path, output_file: str | Path | BinaryIO, _context: PdfContext
+) -> None:
     log.debug('%s -> %s', input_file, output_file)
-    with open(input_file, 'rb') as input_stream:
+    with input_file.open('rb') as input_stream:
         if output_file == '-':
             copyfileobj(input_stream, sys.stdout.buffer)
             sys.stdout.flush()
         elif hasattr(output_file, 'writable'):
-            output_stream = output_file
+            output_stream = cast(BinaryIO, output_file)
             copyfileobj(input_stream, output_stream)
             with suppress(AttributeError):
                 output_stream.flush()
diff --git a/src/ocrmypdf/_sync.py b/src/ocrmypdf/_sync.py
index 54cb0e08..9f077966 100644
--- a/src/ocrmypdf/_sync.py
+++ b/src/ocrmypdf/_sync.py
@@ -418,13 +418,13 @@ def run_pipeline(
                 options, start_input_file, options.output_file, optimize_messages
             )
 
-    except (KeyboardInterrupt if not api else NeverRaise):
+    except KeyboardInterrupt if not api else NeverRaise:
         if options.verbose >= 1:
             log.exception("KeyboardInterrupt")
         else:
             log.error("KeyboardInterrupt")
         return ExitCode.ctrl_c
-    except (ExitCodeException if not api else NeverRaise) as e:
+    except ExitCodeException if not api else NeverRaise as e:
         e = cast(ExitCodeException, e)
         if options.verbose >= 1:
             log.exception("ExitCodeException")
@@ -433,7 +433,7 @@ def run_pipeline(
         else:
             log.error(type(e).__name__)
         return e.exit_code
-    except (PIL.Image.DecompressionBombError if not api else NeverRaise):
+    except PIL.Image.DecompressionBombError if not api else NeverRaise:
         log.exception(
             "A decompression bomb error was encountered while executing the "
             "pipeline. Use the argument --max-image-mpixels to raise the maximum "
@@ -451,7 +451,7 @@ def run_pipeline(
             "argument."
         )
         return ExitCode.child_process_error
-    except (Exception if not api else NeverRaise):  # pylint: disable=broad-except
+    except Exception if not api else NeverRaise:  # pylint: disable=broad-except
         log.exception("An exception occurred while executing the pipeline")
         return ExitCode.other_error
     finally:
diff --git a/src/ocrmypdf/api.py b/src/ocrmypdf/api.py
index 8cc7ee41..a29787db 100644
--- a/src/ocrmypdf/api.py
+++ b/src/ocrmypdf/api.py
@@ -207,51 +207,51 @@ def ocr(  # noqa: ruff: disable=D417
     input_file: PathOrIO,
     output_file: PathOrIO,
     *,
-    language: Iterable[str] = None,
-    image_dpi: int = None,
-    output_type=None,
+    language: Iterable[str] | None = None,
+    image_dpi: int | None = None,
+    output_type: str | None = None,
     sidecar: StrPath | None = None,
-    jobs: int = None,
-    use_threads: bool = None,
-    title: str = None,
-    author: str = None,
-    subject: str = None,
-    keywords: str = None,
-    rotate_pages: bool = None,
-    remove_background: bool = None,
-    deskew: bool = None,
-    clean: bool = None,
-    clean_final: bool = None,
-    unpaper_args: str = None,
-    oversample: int = None,
-    remove_vectors: bool = None,
-    force_ocr: bool = None,
-    skip_text: bool = None,
-    redo_ocr: bool = None,
-    skip_big: float = None,
-    optimize: int = None,
-    jpg_quality: int = None,
-    png_quality: int = None,
-    jbig2_lossy: bool = None,
-    jbig2_page_group_size: int = None,
-    pages: str = None,
-    max_image_mpixels: float = None,
-    tesseract_config: Iterable[str] = None,
-    tesseract_pagesegmode: int = None,
-    tesseract_oem: int = None,
-    tesseract_thresholding: int = None,
-    pdf_renderer=None,
-    tesseract_timeout: float = None,
-    tesseract_non_ocr_timeout: float = None,
-    rotate_pages_threshold: float = None,
-    pdfa_image_compression=None,
-    user_words: os.PathLike = None,
-    user_patterns: os.PathLike = None,
-    fast_web_view: float = None,
-    plugins: Iterable[StrPath] = None,
+    jobs: int | None = None,
+    use_threads: bool | None = None,
+    title: str | None = None,
+    author: str | None = None,
+    subject: str | None = None,
+    keywords: str | None = None,
+    rotate_pages: bool | None = None,
+    remove_background: bool | None = None,
+    deskew: bool | None = None,
+    clean: bool | None = None,
+    clean_final: bool | None = None,
+    unpaper_args: str | None = None,
+    oversample: int | None = None,
+    remove_vectors: bool | None = None,
+    force_ocr: bool | None = None,
+    skip_text: bool | None = None,
+    redo_ocr: bool | None = None,
+    skip_big: float | None = None,
+    optimize: int | None = None,
+    jpg_quality: int | None = None,
+    png_quality: int | None = None,
+    jbig2_lossy: bool | None = None,
+    jbig2_page_group_size: int | None = None,
+    pages: str | None = None,
+    max_image_mpixels: float | None = None,
+    tesseract_config: Iterable[str] | None = None,
+    tesseract_pagesegmode: int | None = None,
+    tesseract_oem: int | None = None,
+    tesseract_thresholding: int | None = None,
+    pdf_renderer: str | None = None,
+    tesseract_timeout: float | None = None,
+    tesseract_non_ocr_timeout: float | None = None,
+    rotate_pages_threshold: float | None = None,
+    pdfa_image_compression: str | None = None,
+    user_words: os.PathLike | None = None,
+    user_patterns: os.PathLike | None = None,
+    fast_web_view: float | None = None,
+    plugins: Iterable[StrPath] | None = None,
     plugin_manager=None,
-    keep_temporary_files: bool = None,
-    progress_bar: bool = None,
+    keep_temporary_files: bool | None = None,
+    progress_bar: bool | None = None,
     **kwargs,
 ):
     """Run OCRmyPDF on one PDF or image.
diff --git a/src/ocrmypdf/extra_plugins/semfree.py b/src/ocrmypdf/extra_plugins/semfree.py
index 231f5f24..6e7dd3c2 100644
--- a/src/ocrmypdf/extra_plugins/semfree.py
+++ b/src/ocrmypdf/extra_plugins/semfree.py
@@ -168,8 +168,7 @@ class LambdaExecutor(Executor):
                         continue
 
                     if msg_type == MessageType.result:
-                        if task_finished:
-                            task_finished(msg, pbar)
+                        task_finished(msg, pbar)
                     elif msg_type == 'log':
                         record = msg
                         logger = logging.getLogger(record.name)
diff --git a/src/ocrmypdf/pdfa.py b/src/ocrmypdf/pdfa.py
index 199c02f1..9be3649a 100644
--- a/src/ocrmypdf/pdfa.py
+++ b/src/ocrmypdf/pdfa.py
@@ -23,8 +23,8 @@ def _postscript_objdef(
     alias: str,
     dictionary: dict[str, str],
     *,
-    stream_name: str = None,
-    stream_data: bytes = None,
+    stream_name: str | None = None,
+    stream_data: bytes | None = None,
 ) -> Iterator[str]:
     assert (stream_name is None) == (stream_data is None)
 
diff --git a/src/ocrmypdf/pdfinfo/info.py b/src/ocrmypdf/pdfinfo/info.py
index 9a18e64d..9c59bc82 100644
--- a/src/ocrmypdf/pdfinfo/info.py
+++ b/src/ocrmypdf/pdfinfo/info.py
@@ -959,7 +959,7 @@ class PdfInfo:
         *,
         detailed_analysis: bool = False,
         progbar: bool = False,
-        max_workers: int = None,
+        max_workers: int | None = None,
         check_pages=None,
         executor: Executor = DEFAULT_EXECUTOR,
     ):
diff --git a/src/ocrmypdf/pluginspec.py b/src/ocrmypdf/pluginspec.py
index de7c19fe..598bd538 100644
--- a/src/ocrmypdf/pluginspec.py
+++ b/src/ocrmypdf/pluginspec.py
@@ -28,6 +28,7 @@ if TYPE_CHECKING:
 hookspec = pluggy.HookspecMarker('ocrmypdf')
 
 # pylint: disable=unused-argument
+# mypy:
 
 
 @hookspec(firstresult=True)
@@ -43,7 +44,7 @@ def get_logging_console() -> Handler:
 
 
 @hookspec
-def initialize(plugin_manager: pluggy.PluginManager):
+def initialize(plugin_manager: pluggy.PluginManager) -> None:
     """Called when this plugin is first loaded into OCRmyPDF.
 
     The primary intended use of this is for plugins to check compatibility with other