amend

tensordict/memmap.py

@@ -133,16 +133,18 @@ def from_tensor(
 
         """
         if isinstance(input, MemoryMappedTensor):
-            if (
-                (filename is None and input._filename is None)
-                or (input._filename is not None and filename is not None and Path(filename).absolute() == Path(input.filename).absolute())
+            if filename is None or (
+                input._filename is not None
+                and filename is not None
+                and Path(filename).absolute() == Path(input.filename).absolute()
             ):
                 # either location was not specified, or memmap is already in the
                 # correct location, so just return the MemmapTensor unmodified
                 return input
-            elif (
-                not copy_existing
-                and (input._filename is not None and filename is not None and Path(filename).absolute() != Path(input.filename).absolute())
+            elif not copy_existing and (
+                input._filename is not None
+                and filename is not None
+                and Path(filename).absolute() != Path(input.filename).absolute()
             ):
                 raise RuntimeError(
                     f"A filename was provided but the tensor already has a file associated "