diff --git a/leap_data_management_utils/cmip_transforms.py b/leap_data_management_utils/cmip_transforms.py
index a0e8f87..122e347 100644
--- a/leap_data_management_utils/cmip_transforms.py
+++ b/leap_data_management_utils/cmip_transforms.py
@@ -9,6 +9,7 @@
 import zarr
 from google.cloud import bigquery
 from pangeo_forge_recipes.transforms import Indexed, T
+from tqdm.auto import tqdm
 
 from leap_data_management_utils.cmip_testing import test_all
 from leap_data_management_utils.data_management_transforms import BQInterface
@@ -136,23 +137,14 @@ def iid_exists(self, iid: str) -> bool:
         """Check if iid exists in the table"""
         return self._get_iid_results(iid).exists
 
-    def iid_list_exists(self, iids: list[str]) -> list[str]:
+    def _iid_list_exists_batch(self, iids: list[str]) -> list[str]:
         """More efficient way to check if a list of iids exists in the table
         Passes the entire list to a single SQL query.
         Returns a list of iids that exist in the table
-        Only supports list up to 10k elements. If you want to check more, you should
-        work in batches:
-        ```
-        iids = df['instance_id'].tolist()
-        iids_in_bq = []
-        batchsize = 10000
-        iid_batches = [iids[i : i + batchsize] for i in range(0, len(iids), batchsize)]
-        for iids_batch in tqdm(iid_batches):
-            iids_in_bq_batch = bq.iid_list_exists(iids_batch)
-            iids_in_bq.extend(iids_in_bq_batch)
         ```
         """
-        assert len(iids) <= 10000
+        if len(iids) > 10000:
+            raise ValueError('List of iids is too long. Please work in batches.')
 
         # source: https://stackoverflow.com/questions/26441928/how-do-i-check-if-multiple-values-exists-in-database
         query = f"""
@@ -164,6 +156,21 @@ def iid_list_exists(self, iids: list[str]) -> list[str]:
         # this is a full row iterator, for now just return the iids
         return list(set([r['instance_id'] for r in results]))
 
+    def iid_list_exists(self, iids: list[str]) -> list[str]:
+        """More efficient way to check if a list of iids exists in the table
+        Passes the entire list in batches into SQL querys for maximum efficiency.
+        Returns a list of iids that exist in the table
+        """
+
+        # make batches of the input, since bq cannot handle more than 10k elements here
+        iids_in_bq = []
+        batchsize = 10000
+        iid_batches = [iids[i : i + batchsize] for i in range(0, len(iids), batchsize)]
+        for iids_batch in tqdm(iid_batches):
+            iids_in_bq_batch = self._iid_list_exists_batch(iids_batch)
+            iids_in_bq.extend(iids_in_bq_batch)
+        return iids_in_bq
+
 
 # ----------------------------------------------------------------------------------------------
 # apache Beam stages
diff --git a/pyproject.toml b/pyproject.toml
index 6e7b04e..f31140a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,6 +31,7 @@ dependencies = [
 [project.optional-dependencies]
 
 pangeo-forge=[
+    "tqdm",
     "db_dtypes",
     "google-api-core",
     "google-cloud-bigquery",