Make prospector happy

Also, use flynt to detect string formatting issues.

pyproject.toml

@@ -20,6 +20,7 @@ types-dateparser = "^1.1.0"
 types-requests = "^2.27.16"
 types-Markdown = "^3.3.12"
 prospector = "^1.7.7"
+flynt = "^0.76"
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]

scripts/update-seminars.py

@@ -50,12 +50,11 @@ def _normalize_key(key):
 
         if attrs and contents:
             return f"<{tag_name} {attrs}>{contents}</{tag_name}>"
-        elif attrs:
+        if attrs:
             return f"<{tag_name} {attrs} />"
-        elif contents:
+        if contents:
             return f"<{tag_name}>{contents}</{tag_name}>"
-        else:
-            return f"<{tag_name} />"
+        return f"<{tag_name} />"
 
     return _tag
 
@@ -128,6 +127,7 @@ def _speaker_avatar_to_markdown(self):
                 ),
                 href=self.speaker_url,
             )
+        return None
 
     def _description_to_markdown(self):
         return markdown(self.description)
@@ -191,8 +191,8 @@ def __post_init__(self):
         calendar.HTMLCalendar()
         .formatmonth(datetime.today().year, datetime.today().month)
         .replace(
-            ">%i<" % datetime.today().day,
-            ' bgcolor="#66ff66"><b><u>%i</u></b><' % datetime.today().day,
+            f">{int(datetime.today().day)}<",
+            f' bgcolor="#66ff66"><b><u>{int(datetime.today().day)}</u></b><',
         )
     )