diff --git a/scripts/common.py b/scripts/common.py
index 661ce1ddb8b0a56f8ffbcf507a64f173225d9936..e9d318624ee0f4281aad628029e5a45ec4de8ab8 100644
--- a/scripts/common.py
+++ b/scripts/common.py
@@ -619,6 +619,7 @@ def is_multicolumn(filename, algorithm='computational_geometry'):
 def _get_number_of_columns_computational_geometry(xml_document, num_beams=5):
     page, = xml_document.xpath('//div[@class="ocr_page"]')
     page_match = re.match(BBOX_REGEX, page.attrib['title'])
+    assert page_match is not None
     page_height = float(page_match.group('y1')) - float(page_match.group('y0'))
 
     from shapely.geometry import Polygon, LineString
@@ -626,6 +627,7 @@ def _get_number_of_columns_computational_geometry(xml_document, num_beams=5):
     paragraphs = []
     for paragraph_number, paragraph in enumerate(page.xpath('//p[@class="ocr_par" and @title]')):
         paragraph_match = re.match(BBOX_REGEX, paragraph.attrib['title'])
+        assert paragraph_match is not None
         coords = [
             (float(paragraph_match.group('x0')), float(paragraph_match.group('y0'))),
             (float(paragraph_match.group('x0')), float(paragraph_match.group('y1'))),
diff --git a/scripts/evaluate_speed_piechart.py b/scripts/evaluate_speed_piechart.py
index 2e23498eb5a411843cfa96c4b36a9f89776b7a72..20846425bb9f122e54c80c5d66487d392dd1d6e1 100644
--- a/scripts/evaluate_speed_piechart.py
+++ b/scripts/evaluate_speed_piechart.py
@@ -39,6 +39,7 @@ def evaluate():
         if exit_code != 0:
             continue
         match = re.fullmatch(COMMAND_REGEX, command)
+        assert match is not None
         command = list(dropwhile(lambda x: x is None, match.groups()))[0]
         if command not in LABEL_MAP:
             if command not in missing_commands: