Additional ruff fixes

src/ocrmypdf/builtin_plugins/concurrency.py

@@ -54,6 +54,7 @@ def log_listener(q: Queue):
 
 
 def process_sigbus(*args):
+    """Handle SIGBUS signal at the worker level."""
     raise InputFileError("A worker process lost access to an input file")
 
 
@@ -80,6 +81,7 @@ def process_init(q: Queue, user_init: UserInit, loglevel) -> None:
 
 
 def thread_init(q: Queue, user_init: UserInit, loglevel) -> None:
+    """Begin a thread pool worker."""
     del q  # unused but required argument
     del loglevel  # unused but required argument
     # As a thread, block SIGBUS so the main thread deals with it...
@@ -162,14 +164,17 @@ class StandardExecutor(Executor):
 
 @hookimpl
 def get_executor(progressbar_class):
+    """Return the default executor."""
     return StandardExecutor(pbar_class=progressbar_class)
 
 
 @hookimpl
 def get_progressbar_class():
+    """Return the default progress bar class."""
     return tqdm
 
 
 @hookimpl
 def get_logging_console():
+    """Return the default logging console handler."""
     return logging.StreamHandler(stream=TqdmConsole(sys.stderr))

src/ocrmypdf/builtin_plugins/ghostscript.py

@@ -16,6 +16,7 @@ log = logging.getLogger(__name__)
 
 @hookimpl
 def check_options(options):
+    """Check that the options are valid for this plugin."""
     check_external_program(
         program='gs',
         package='ghostscript',
@@ -45,6 +46,7 @@ def rasterize_pdf_page(
     rotation,
     filter_vector,
 ):
+    """Rasterize a single page of a PDF file using Ghostscript."""
     ghostscript.rasterize_pdf(
         input_file,
         output_file,
@@ -68,6 +70,7 @@ def generate_pdfa(
     pdfa_part,
     progressbar_class,
 ):
+    """Generate a PDF/A from the list of PDF pages and PDF/A metadata."""
     ghostscript.generate_pdfa(
         pdf_pages=[*pdf_pages, pdfmark],
         output_file=output_file,