diff --git a/src/spikeinterface/core/generate.py b/src/spikeinterface/core/generate.py
index 88c63ea30a..ec76fcbaa9 100644
--- a/src/spikeinterface/core/generate.py
+++ b/src/spikeinterface/core/generate.py
@@ -1,5 +1,4 @@
 from __future__ import annotations
-
 import math
 import warnings
 import numpy as np
@@ -908,9 +907,9 @@ def inject_some_duplicate_units(sorting, num=4, max_shift=5, ratio=None, seed=No
     return sorting_with_dup
 
 
-def inject_some_split_units(sorting, split_ids=[], num_split=2, output_ids=False, seed=None):
+def inject_some_split_units(sorting, split_ids: list, num_split=2, output_ids=False, seed=None):
     """ """
-    assert len(split_ids) > 0, "you need to provide some ids to split"
+
     unit_ids = sorting.unit_ids
     assert unit_ids.dtype.kind == "i"
 
@@ -1444,7 +1443,8 @@ def generate_templates(
     seed=None,
     dtype="float32",
     upsample_factor=None,
-    unit_params=dict(),
+    unit_params=None,
+    unit_params_range=None,
     mode="ellipsoid",
 ):
     """
@@ -1501,6 +1501,9 @@ def generate_templates(
             * (num_units, num_samples, num_channels, upsample_factor) if upsample_factor is not None
 
     """
+
+    unit_params = unit_params or dict()
+    unit_params_range = unit_params_range or dict()
     rng = np.random.default_rng(seed=seed)
 
     # neuron location must be 3D
@@ -1968,7 +1971,7 @@ def generate_ground_truth_recording(
     generate_sorting_kwargs=dict(firing_rates=15, refractory_period_ms=4.0),
     noise_kwargs=dict(noise_levels=5.0, strategy="on_the_fly"),
     generate_unit_locations_kwargs=dict(margin_um=10.0, minimum_z=5.0, maximum_z=50.0, minimum_distance=20),
-    generate_templates_kwargs=dict(),
+    generate_templates_kwargs=None,
     dtype="float32",
     seed=None,
 ):
@@ -2027,6 +2030,7 @@ def generate_ground_truth_recording(
     sorting: Sorting
         The generated sorting extractor.
     """
+    generate_templates_kwargs = generate_templates_kwargs or dict()
 
     # TODO implement upsample_factor in InjectTemplatesRecording and propagate into toy_example
 
diff --git a/src/spikeinterface/curation/tests/test_auto_merge.py b/src/spikeinterface/curation/tests/test_auto_merge.py
index f8dea5b270..bbf861dac9 100644
--- a/src/spikeinterface/curation/tests/test_auto_merge.py
+++ b/src/spikeinterface/curation/tests/test_auto_merge.py
@@ -25,14 +25,15 @@ def test_get_auto_merge_list(sorting_analyzer_for_curation):
     num_unit_splited = 1
     num_split = 2
 
+    split_ids = sorting.unit_ids[:num_unit_splited]
     sorting_with_split, other_ids = inject_some_split_units(
-        sorting, split_ids=sorting.unit_ids[:num_unit_splited], num_split=num_split, output_ids=True, seed=42
+        sorting,
+        split_ids=split_ids,
+        num_split=num_split,
+        output_ids=True,
+        seed=42,
     )
 
-    # print(sorting_with_split)
-    # print(sorting_with_split.unit_ids)
-    # print(other_ids)
-
     job_kwargs = dict(n_jobs=-1)
 
     sorting_analyzer = create_sorting_analyzer(sorting_with_split, recording, format="memory")
@@ -59,8 +60,6 @@ def test_get_auto_merge_list(sorting_analyzer_for_curation):
         firing_contamination_balance=1.5,
         extra_outputs=True,
     )
-    # print(potential_merges)
-    # print(num_unit_splited)
 
     assert len(potential_merges) == num_unit_splited
     for true_pair in other_ids.values():