[MNT] use deepcopy when set_metainfo

abl/structures/base_data_element.py

@@ -227,8 +227,8 @@ class BaseDataElement:
         assert isinstance(
             metainfo, dict
         ), f"metainfo should be a ``dict`` but got {type(metainfo)}"
-        # meta = copy.deepcopy(metainfo)
-        for k, v in metainfo.items():
+        meta = copy.deepcopy(metainfo)
+        for k, v in meta.items():
             self.set_field(name=k, value=v, field_type="metainfo", dtype=None)
 
     def set_data(self, data: dict) -> None: