diff --git a/liger_iris_pipeline/dark_current/dark_current_step.py b/liger_iris_pipeline/dark_current/dark_current_step.py
index ebca3fd..d7d13f1 100644
--- a/liger_iris_pipeline/dark_current/dark_current_step.py
+++ b/liger_iris_pipeline/dark_current/dark_current_step.py
@@ -22,19 +22,6 @@ class DarkCurrentStep(Step):
 
     reference_file_types = ["dark"]
 
-    #FIXME - This will need to be ported to a new LigerIrisStep class
-    # I do not understand why this is necessary, in JWST it seems like
-    # this is not needed and works out of the box.
-    # Without this, the pipeline tries to call `datamodes.open` on a
-    # file that is already open, which gives the error:
-    # expected str, bytes or os.PathLike object, not LigerIrisDataModel
-    @classmethod
-    def _datamodels_open(cls, init, **kwargs):
-        if issubclass(init.__class__, stdatamodels.model_base.DataModel):
-            return init
-        else:
-            return datamodels.open(init, **kwargs)
-
     def process(self, input):
 
         # Open the input data model
diff --git a/liger_iris_pipeline/datamodels/model_base.py b/liger_iris_pipeline/datamodels/model_base.py
index 2593cf8..ad13468 100644
--- a/liger_iris_pipeline/datamodels/model_base.py
+++ b/liger_iris_pipeline/datamodels/model_base.py
@@ -1,6 +1,6 @@
 from astropy.time import Time
 
-from stdatamodels import DataModel as _DataModel
+from stdatamodels.jwst.datamodels import JwstDataModel as _DataModel
 
 
 __all__ = ["LigerIrisDataModel"]
@@ -30,7 +30,8 @@ def get_crds_parameters(self):
         dict
         """
         return {
-            key: val for key, val in self.to_flat_dict(include_arrays=False).items()
+            key: val
+            for key, val in self.to_flat_dict(include_arrays=False).items()
             if isinstance(val, (str, int, float, complex, bool))
         }
 
@@ -51,4 +52,4 @@ def on_save(self, init):
         """
         super().on_save(init)
 
-        self.meta.date = Time.now().isot
\ No newline at end of file
+        self.meta.date = Time.now().isot