Internal change

checkpoint/orbax/checkpoint/_src/arrays/fragments.py

@@ -178,18 +178,26 @@ def slice(
     stop = out.stop[:] = np.minimum(out.stop, slice_shape)
     if not (start < stop).all():
       return None
-    if (value := self.value) is None:
-      return out
-    else:
-      value_fragment = Fragment(
-          np_index=np.stack([
-              np.maximum(self.start, np_index[:, 0]),
-              np.minimum(self.stop, np_index[:, 1]),
-              np_index[:, 2],
-          ], axis=1)
-      ).offset_by(-self.start)
-      out_value = value[value_fragment.index or ...]
-      return dataclasses.replace(out, value=out_value)
+    return dataclasses.replace(
+        out, value=self.slice_of_value(np_index)
+    ) if self.value is not None else out
+
+  def slice_of_value(
+      self,
+      new_np_idx: NpIndex,
+  ) -> np.ndarray:
+    """Returns a slice of `value`."""
+    start = self.start
+    stop = self.stop
+    # This is just a convenient way to construct the required tuple of slices.
+    f = Fragment(
+        np_index=np.stack([
+            np.maximum(start, new_np_idx[:, 0]),
+            np.minimum(stop, new_np_idx[:, 1]),
+            new_np_idx[:, 2],
+        ], axis=1)
+    ).offset_by(-start)
+    return self.value[f.index or ...]
 
 
 @dataclasses.dataclass(frozen=True)