Annotate type of main function, refactor for mypy, rename fatal_warnings variable

Author: m-aciek

Doc/tools/check-epub.py

@@ -2,24 +2,22 @@
 from pathlib import Path
 
 
-def main():
+def main() -> int:
     wrong_directory_msg = "Must run this script from the repo root"
     if not Path("Doc").exists() or not Path("Doc").is_dir():
         raise RuntimeError(wrong_directory_msg)
 
     with Path("Doc/epubcheck.txt").open(encoding="UTF-8") as f:
-        warnings = f.read().splitlines()
+        warnings = [warning.split(" - ") for warning in f.read().splitlines()]
 
-    warnings = [warning.split(" - ") for warning in warnings]
+    fatal_warnings = [warning for warning in warnings if warning[0] == "FATAL"]
 
-    fatals = [warning for warning in warnings if warning[0] == "FATAL"]
-
-    if fatals:
+    if fatal_warnings:
         print("\nError: must not contain fatal errors:\n")
-        for fatal in fatals:
-            print(" - ".join(fatal))
+        for warning in fatal_warnings:
+            print(" - ".join(warning))
 
-    return len(fatals)
+    return len(fatal_warnings)
 
 
 if __name__ == "__main__":