fix: graceful fallback

app.py

@@ -24,7 +24,7 @@
 
 import marimo
 
-__generated_with = "0.14.9"
+__generated_with = "0.14.10"
 app = marimo.App(width="full", app_title="Scattertext on English novels")
 
 with app.setup:
@@ -100,7 +100,12 @@ def function_export():
         E.g., 'e-r-eddison_the-worm-ouroboros.txt' -> 'ERE-TWO'.
         """
         stem = _strip_advanced(fn)
-        author, title = stem.split("_", 1)
+        fields = stem.split("_", 1)
+        if len(fields) == 2:
+            author, title = fields
+        else:
+            author = fields[0]
+            title = fields[0]
         initials = lambda s: "".join(part[0].upper() for part in s.split("-"))
         return f"{initials(author)}-{initials(title)}"