diff --git a/docs/tools/build.py b/docs/tools/build.py
index 04ee2638220..4ba9a82d7b2 100755
--- a/docs/tools/build.py
+++ b/docs/tools/build.py
@@ -258,7 +258,7 @@ def build_single_page_version(lang, args, cfg):
                                 logging.info(' '.join(create_pdf_command))
                                 subprocess.check_call(' '.join(create_pdf_command), shell=True)
                             finally:
-                                logging.info(f"Stop serving for {lang} pdf at port {port_for_pdf}"))
+                                logging.info(f'Stop serving for {lang} pdf at port {port_for_pdf}')
                                 process.kill()
                                 while True:
                                     time.sleep(0.25)
@@ -266,7 +266,7 @@ def build_single_page_version(lang, args, cfg):
                                         process.close()
                                         break
                                     except ValueError:
-                                        logging.info(f"Waiting for {lang} httpd at port {port_for_pdf} to stop")
+                                        logging.info(f'Waiting for {lang} httpd at port {port_for_pdf} to stop')
 
 
                     if not args.version_prefix:  # maybe enable in future