Add comment about prefix count

psf · Jan 13, 2022 · d1da9b9 · d1da9b9
1 parent d7b0a5f
commit d1da9b9
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/src/black/strings.py b/src/black/strings.py
@@ -150,6 +150,7 @@ def normalize_string_prefix(s: str) -> str:
         .replace("u", "")
     )
 
+    # Python syntax guarantees max 2 prefixes and that one of them is "r"
     if len(new_prefix) == 2 and "r" != new_prefix[0].lower():
         new_prefix = new_prefix[::-1]
     return f"{new_prefix}{match.group(2)}"