diff --git a/ale/base/label_isis.py b/ale/base/label_isis.py
index 28d1642d2..2a42ec02d 100644
--- a/ale/base/label_isis.py
+++ b/ale/base/label_isis.py
@@ -12,12 +12,13 @@ def label(self):
                 self._label = self._file
             grammar = pvl.grammar.ISISGrammar()
             grammar.comments+=(("#", "\n"), )
-            try:
-                self._label = pvl.loads(self._file, grammar=grammar)
-            except Exception:
-                self._label = pvl.load(self._file, grammar=grammar)
-            except:
-                raise ValueError("{} is not a valid label".format(self._file))
+            if not isinstance(self._file, pvl.PVLModule):
+                try:
+                    self._label = pvl.loads(self._file, grammar=grammar)
+                except Exception:
+                    self._label = pvl.load(self._file, grammar=grammar)
+                except:
+                    raise ValueError("{} is not a valid label".format(self._file))
         return self._label
 
     @property