MapDatasetWrapper: support for external seq_order

Author: patrick-wilken

returnn/datasets/map.py

@@ -102,8 +102,11 @@ def init_seq_order(self, epoch=None, seq_list=None, seq_order=None):
     """
     super(MapDatasetWrapper, self).init_seq_order(epoch=epoch, seq_list=seq_list, seq_order=seq_order)
 
-    if seq_list or seq_order:
+    if seq_list:
       raise NotImplementedError
+    if seq_order:
+      self._seq_order = seq_order
+      return True
 
     try:
       self._seq_order = self._dataset.get_seq_order(epoch=epoch)