diff --git a/acegen/models/utils.py b/acegen/models/utils.py
index 0225b23..1e70383 100644
--- a/acegen/models/utils.py
+++ b/acegen/models/utils.py
@@ -1,7 +1,5 @@
 import warnings
 
-from torchrl.envs import Compose
-
 
 def adapt_state_dict(source_state_dict: dict, target_state_dict: dict):
     """Adapt the source state dict to the target state dict.
@@ -34,22 +32,3 @@ def adapt_state_dict(source_state_dict: dict, target_state_dict: dict):
         target_state_dict[key_target] = value_source
 
     return target_state_dict
-
-
-def get_primers_from_module(module):
-    """Get all tensordict primers from all submodules of a module."""
-    primers = []
-
-    def make_primers(submodule):
-        if hasattr(submodule, "make_tensordict_primer"):
-            primers.append(submodule.make_tensordict_primer())
-
-    module.apply(make_primers)
-    if not primers:
-        import warnings
-
-        raise warnings.warn("No primers found in the module.")
-    elif len(primers) == 1:
-        return primers[0]
-    else:
-        return Compose(primers)
diff --git a/tests/test_data_utils.py b/tests/test_data_utils.py
index 0497b27..8fc3203 100644
--- a/tests/test_data_utils.py
+++ b/tests/test_data_utils.py
@@ -11,6 +11,7 @@
     smiles_to_tensordict,
     SMILESDataset,
 )
+from acegen.data.chem_utils import fraction_valid
 from acegen.vocabulary.tokenizers import SMILESTokenizerChEMBL
 from acegen.vocabulary.vocabulary import Vocabulary
 from tensordict import TensorDict
@@ -102,3 +103,21 @@ def test_load_dataset(randomize_smiles):
     data_batch = dataloader.__iter__().__next__()
     assert isinstance(data_batch, TensorDict)
     shutil.rmtree(temp_dir)
+
+
+def test_fraction_valid():
+
+    multiple_smiles = [
+        "CCO",  # Ethanol (C2H5OH)
+        "CCN(CC)CC",  # Triethylamine (C6H15N)
+        "CC(=O)OC(C)C",  # Diethyl carbonate (C7H14O3)
+        "CC(C)C",  # Isobutane (C4H10)
+        "CC1=CC=CC=C1",  # Toluene (C7H8)
+    ]
+
+    assert fraction_valid(multiple_smiles) == 1.0
+
+    # add an invalid SMILES
+    multiple_smiles.append("invalid")
+
+    assert fraction_valid(multiple_smiles) == 5 / 6