diff --git a/PyTeX/format/pytex_formatter.py b/PyTeX/format/pytex_formatter.py
index cc62aad..a352809 100644
--- a/PyTeX/format/pytex_formatter.py
+++ b/PyTeX/format/pytex_formatter.py
@@ -169,10 +169,11 @@ class PyTeXFormatter(FormatterIF, ABC):
 
     @property
     def raw_name(self) -> str:
-        try:
-            return self._input_file.name.split('.', maxsplit=1)[0]
-        except:
-            raise NotImplementedError
+        parts = self._input_file.name.split('.', maxsplit=1)
+        if not len(parts) == 2:
+            raise NotImplementedError  # invalid file name
+        else:
+            return parts[0]
 
     @property
     def name(self):