diff --git a/doc/source/tutorials/notebooks/DCSC_txnn.ipynb b/doc/source/tutorials/notebooks/DCSC_txnn.ipynb
index 8cc628ad..963e128b 100644
--- a/doc/source/tutorials/notebooks/DCSC_txnn.ipynb
+++ b/doc/source/tutorials/notebooks/DCSC_txnn.ipynb
@@ -47,19 +47,19 @@
     }
    ],
    "source": [
-    "import datetime\n",
     "import sys\n",
     "from pathlib import Path\n",
     "\n",
     "import cartopy.crs as ccrs\n",
     "import cftime\n",
-    "import icclim\n",
     "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "import xclim\n",
-    "from xclim.core.calendar import select_time \n",
+    "from xclim.core.calendar import select_time\n",
+    "\n",
+    "import icclim\n",
     "from icclim.frequency import FrequencyRegistry\n",
     "\n",
     "print(\"python: \", sys.version)\n",
@@ -68,7 +68,7 @@
     "print(\"pandas: \", pd.__version__)\n",
     "print(\"icclim: \", icclim.__version__)\n",
     "print(\"cftime: \", cftime.__version__)\n",
-    "print(\"xclim: \", xclim.__version__)\n"
+    "print(\"xclim: \", xclim.__version__)"
    ]
   },
   {
@@ -664,7 +664,9 @@
    ],
    "source": [
     "historical_tas = xr.open_mfdataset(historical_files).tas\n",
-    "filtered_tas = select_time(historical_tas, month=FrequencyRegistry.AMJJAS.indexer[\"month\"], drop=True)\n",
+    "filtered_tas = select_time(\n",
+    "    historical_tas, month=FrequencyRegistry.AMJJAS.indexer[\"month\"], drop=True\n",
+    ")\n",
     "normal = filtered_tas.mean(dim=\"time\", keep_attrs=True)\n",
     "normal"
    ]
@@ -1291,7 +1293,7 @@
    "source": [
     "icclim.dcsc.txnd(\n",
     "    in_files=studied_files[0:1],\n",
-    "    normal = normal,\n",
+    "    normal=normal,\n",
     "    var_name=\"tas\",\n",
     "    slice_mode=FrequencyRegistry.AMJJAS,\n",
     "    out_file=out_f,\n",
diff --git a/doc/source/tutorials/notebooks/averaged_tas_anomaly.ipynb b/doc/source/tutorials/notebooks/averaged_tas_anomaly.ipynb
index 80ac16e7..0d86bbed 100644
--- a/doc/source/tutorials/notebooks/averaged_tas_anomaly.ipynb
+++ b/doc/source/tutorials/notebooks/averaged_tas_anomaly.ipynb
@@ -125,13 +125,13 @@
     "import sys\n",
     "from pathlib import Path\n",
     "\n",
-    "import icclim\n",
-    "\n",
     "# provides cftime axis in matplotlib\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "\n",
+    "import icclim\n",
+    "\n",
     "print(\"python: \", sys.version)\n",
     "print(\"numpy: \", np.__version__)\n",
     "print(\"xarray: \", xr.__version__)\n",
diff --git a/doc/source/tutorials/notebooks/cold_spell_duration.ipynb b/doc/source/tutorials/notebooks/cold_spell_duration.ipynb
index d5c60d24..cca7885c 100644
--- a/doc/source/tutorials/notebooks/cold_spell_duration.ipynb
+++ b/doc/source/tutorials/notebooks/cold_spell_duration.ipynb
@@ -333,9 +333,6 @@
     "# CDS API\n",
     "import cdsapi\n",
     "\n",
-    "# icclim package for calculating climate indices\n",
-    "import icclim\n",
-    "\n",
     "# Libraries for plotting and visualising data\n",
     "import matplotlib.pyplot as plt\n",
     "\n",
@@ -346,6 +343,9 @@
     "import urllib3\n",
     "import xarray as xr\n",
     "\n",
+    "# icclim package for calculating climate indices\n",
+    "import icclim\n",
+    "\n",
     "# To add specific units spelling\n",
     "\n",
     "urllib3.disable_warnings()\n",
diff --git a/doc/source/tutorials/notebooks/custom_freezing_tas.ipynb b/doc/source/tutorials/notebooks/custom_freezing_tas.ipynb
index a8e6ed29..280c147b 100644
--- a/doc/source/tutorials/notebooks/custom_freezing_tas.ipynb
+++ b/doc/source/tutorials/notebooks/custom_freezing_tas.ipynb
@@ -129,12 +129,13 @@
     "\n",
     "import cartopy.crs as ccrs\n",
     "import cftime\n",
-    "import icclim\n",
     "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "\n",
+    "import icclim\n",
+    "\n",
     "print(\"python: \", sys.version)\n",
     "print(\"numpy: \", np.__version__)\n",
     "print(\"xarray: \", xr.__version__)\n",
diff --git a/doc/source/tutorials/notebooks/deltaT_deltaP_anomaly.ipynb b/doc/source/tutorials/notebooks/deltaT_deltaP_anomaly.ipynb
index 88fc8b51..548e3102 100644
--- a/doc/source/tutorials/notebooks/deltaT_deltaP_anomaly.ipynb
+++ b/doc/source/tutorials/notebooks/deltaT_deltaP_anomaly.ipynb
@@ -131,12 +131,13 @@
     "from pathlib import Path\n",
     "\n",
     "import cftime\n",
-    "import icclim\n",
     "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "\n",
+    "import icclim\n",
+    "\n",
     "print(\"python: \", sys.version)\n",
     "print(\"numpy: \", np.__version__)\n",
     "print(\"xarray: \", xr.__version__)\n",
diff --git a/doc/source/tutorials/notebooks/su_summer_days__subset_and_plot.ipynb b/doc/source/tutorials/notebooks/su_summer_days__subset_and_plot.ipynb
index 2a6247f7..b01aa1f5 100644
--- a/doc/source/tutorials/notebooks/su_summer_days__subset_and_plot.ipynb
+++ b/doc/source/tutorials/notebooks/su_summer_days__subset_and_plot.ipynb
@@ -129,12 +129,13 @@
     "\n",
     "import cartopy.crs as ccrs\n",
     "import cftime\n",
-    "import icclim\n",
     "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "\n",
+    "import icclim\n",
+    "\n",
     "print(\"python: \", sys.version)\n",
     "print(\"numpy: \", np.__version__)\n",
     "print(\"xarray: \", xr.__version__)\n",
diff --git a/doc/source/tutorials/notebooks/tg90p_calculate__subset_and_plot.ipynb b/doc/source/tutorials/notebooks/tg90p_calculate__subset_and_plot.ipynb
index fa90e28e..4ab780eb 100644
--- a/doc/source/tutorials/notebooks/tg90p_calculate__subset_and_plot.ipynb
+++ b/doc/source/tutorials/notebooks/tg90p_calculate__subset_and_plot.ipynb
@@ -133,12 +133,13 @@
     "import cartopy.crs as ccrs\n",
     "import cftime\n",
     "import dask\n",
-    "import icclim\n",
     "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pandas as pd\n",
     "import xarray as xr\n",
     "\n",
+    "import icclim\n",
+    "\n",
     "print(\"python: \", sys.version)\n",
     "print(\"numpy: \", np.__version__)\n",
     "print(\"pandas: \", pd.__version__)\n",
diff --git a/src/icclim/_core/generic/threshold/percentile.py b/src/icclim/_core/generic/threshold/percentile.py
index 7d1e7660..b7bffd12 100644
--- a/src/icclim/_core/generic/threshold/percentile.py
+++ b/src/icclim/_core/generic/threshold/percentile.py
@@ -333,7 +333,7 @@ def compute(
                 self.value,
                 op,
                 self.is_doy_per_threshold,
-                kwargs.get("freq", None),
+                kwargs.get("freq"),
                 kwargs.get("bootstrap", False),
             )
         msg = (
diff --git a/tests/test_cf_calendar.py b/tests/test_cf_calendar.py
index e5980072..d318878c 100644
--- a/tests/test_cf_calendar.py
+++ b/tests/test_cf_calendar.py
@@ -4,6 +4,7 @@
 import pandas as pd
 import pytest
 import xarray as xr
+
 from icclim._core.model.cf_calendar import CfCalendarRegistry
 from icclim.exception import InvalidIcclimArgumentError
 
diff --git a/tests/test_dcsc.py b/tests/test_dcsc.py
index 600789f5..fea4ddd8 100644
--- a/tests/test_dcsc.py
+++ b/tests/test_dcsc.py
@@ -1,5 +1,4 @@
 from icclim.dcsc import txnd
-
 from tests.testing_utils import stub_tas
 
 
diff --git a/tests/test_ecad_indices.py b/tests/test_ecad_indices.py
index f0b61c51..39ddd855 100644
--- a/tests/test_ecad_indices.py
+++ b/tests/test_ecad_indices.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import pytest
+
 from icclim._core.model.standard_index import StandardIndex
 from icclim.ecad.registry import EcadIndexRegistry
 from icclim.exception import InvalidIcclimArgumentError
diff --git a/tests/test_frequency.py b/tests/test_frequency.py
index b9ca1901..195fe16d 100644
--- a/tests/test_frequency.py
+++ b/tests/test_frequency.py
@@ -4,9 +4,9 @@
 import numpy as np
 import pandas as pd
 import pytest
+
 from icclim.exception import InvalidIcclimArgumentError
 from icclim.frequency import FrequencyRegistry, get_seasonal_time_updater
-
 from tests.testing_utils import stub_tas
 
 
diff --git a/tests/test_generated_api.py b/tests/test_generated_api.py
index b971e026..42c4307e 100644
--- a/tests/test_generated_api.py
+++ b/tests/test_generated_api.py
@@ -4,9 +4,10 @@
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
 
-import icclim
 import numpy as np
 import pytest
+
+import icclim
 from icclim._core.constants import QUANTILE_BASED, REFERENCE_PERIOD_INDEX
 from icclim._core.legacy.user_index.calc_operation import (
     CalcOperation,
@@ -20,7 +21,6 @@
 from icclim.generic.registry import GenericIndicatorRegistry
 from icclim.logger import VerbosityRegistry
 from icclim.threshold.factory import build_threshold
-
 from tests.testing_utils import stub_tas
 
 if TYPE_CHECKING:
@@ -137,7 +137,7 @@ def test_txx__season_slice_mode() -> None:
     res = icclim.txx(tas, slice_mode=["season", [11, 12, 1, 2]]).compute()
     # THEN
     # missing values for nov, dec of first period
-    np.testing.assert_array_equal(res.TXx.isel(time=0), np.NAN)
+    np.testing.assert_array_equal(res.TXx.isel(time=0), np.nan)
     np.testing.assert_array_equal(res.TXx.isel(time=1), 30.0)
     np.testing.assert_array_equal(
         res.time_bounds.isel(time=0),
@@ -151,7 +151,7 @@ def test_txx__months_slice_mode() -> None:
     tas.loc[{"time": "2042-01-01"}] = 303.15  # 30°C 273.15
     res = icclim.txx(tas, slice_mode=["months", [11, 1]]).compute()
     np.testing.assert_array_equal(res.TXx.isel(time=0), 30)
-    np.testing.assert_array_equal(res.TXx.isel(time=1), np.NAN)
+    np.testing.assert_array_equal(res.TXx.isel(time=1), np.nan)
     np.testing.assert_almost_equal(res.TXx.sel(time="2042-11"), 21.85)
     np.testing.assert_array_equal(
         res.time_bounds.isel(time=0),
@@ -192,8 +192,8 @@ def test_custom_index__season_slice_mode(
         },
     ).compute()
     # missing values algo applied for first and last years
-    np.testing.assert_almost_equal(res.pouet.isel(time=0), np.NAN)
-    np.testing.assert_almost_equal(res.pouet.isel(time=-1), np.NAN)
+    np.testing.assert_almost_equal(res.pouet.isel(time=0), np.nan)
+    np.testing.assert_almost_equal(res.pouet.isel(time=-1), np.nan)
     np.testing.assert_almost_equal(res.pouet.isel(time=1), expectation_year_1)
     np.testing.assert_almost_equal(res.pouet.isel(time=2), expectation_year_2)
 
@@ -225,8 +225,8 @@ def test_custom_index_run_algos__season_slice_mode(
         },
     )
     # missing values algo applied for first and last years
-    np.testing.assert_almost_equal(res.pouet.isel(time=0), np.NAN)
-    np.testing.assert_almost_equal(res.pouet.isel(time=-1), np.NAN)
+    np.testing.assert_almost_equal(res.pouet.isel(time=0), np.nan)
+    np.testing.assert_almost_equal(res.pouet.isel(time=-1), np.nan)
     np.testing.assert_almost_equal(res.pouet.isel(time=1), expectation_year_1)
     np.testing.assert_almost_equal(res.pouet.isel(time=2), expectation_year_2)
 
@@ -280,12 +280,12 @@ def test_custom_index_anomaly__datetime_ref_period() -> None:
         },
     ).compute()
     # missing values algo applied for first and last years
-    np.testing.assert_almost_equal(res.anomaly.sel(time="2041"), np.NAN)
+    np.testing.assert_almost_equal(res.anomaly.sel(time="2041"), np.nan)
     np.testing.assert_almost_equal(res.anomaly.sel(time="2042"), 0)
     np.testing.assert_almost_equal(res.anomaly.sel(time="2043"), 0)
     np.testing.assert_almost_equal(res.anomaly.sel(time="2044"), 4.80645161)
     np.testing.assert_almost_equal(res.anomaly.sel(time="2045"), 0)
-    np.testing.assert_almost_equal(res.anomaly.sel(time="2046"), np.NAN)
+    np.testing.assert_almost_equal(res.anomaly.sel(time="2046"), np.nan)
 
 
 def test_custom_index_anomaly__groupby_and_resample_month() -> None:
diff --git a/tests/test_generic_functions.py b/tests/test_generic_functions.py
index c6961f6a..474eae6b 100644
--- a/tests/test_generic_functions.py
+++ b/tests/test_generic_functions.py
@@ -4,7 +4,6 @@
 from icclim._core.model.standard_variable import StandardVariableRegistry
 from icclim.frequency import FrequencyRegistry
 from icclim.threshold.factory import build_threshold
-
 from tests.testing_utils import stub_tas
 
 
diff --git a/tests/test_index_group.py b/tests/test_index_group.py
index 92279e5b..04317296 100644
--- a/tests/test_index_group.py
+++ b/tests/test_index_group.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import pytest
+
 from icclim._core.model.index_group import IndexGroupRegistry
 from icclim.exception import InvalidIcclimArgumentError
 
diff --git a/tests/test_input_parsing.py b/tests/test_input_parsing.py
index e364296a..4a81ae4f 100644
--- a/tests/test_input_parsing.py
+++ b/tests/test_input_parsing.py
@@ -8,6 +8,7 @@
 import pandas as pd
 import pytest
 import xarray as xr
+
 from icclim._core.constants import UNITS_KEY
 from icclim._core.input_parsing import (
     PercentileDataArray,
diff --git a/tests/test_main.py b/tests/test_main.py
index a642c812..3944c3a7 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -6,12 +6,13 @@
 from unittest.mock import MagicMock, patch
 
 import cftime
-import icclim
 import numpy as np
 import pandas as pd
 import pint
 import pytest
 import xarray as xr
+
+import icclim
 from icclim import __version__ as icclim_version
 from icclim._core.constants import PART_OF_A_WHOLE_UNIT, REFERENCE_PERIOD_ID, UNITS_KEY
 from icclim._core.model.index_group import IndexGroupRegistry
@@ -19,7 +20,6 @@
 from icclim.exception import InvalidIcclimArgumentError
 from icclim.frequency import FrequencyRegistry
 from icclim.threshold.factory import build_threshold
-
 from tests.testing_utils import K2C, stub_pr, stub_tas
 
 
@@ -38,7 +38,7 @@ def test_deprecated_indice(log_mock: MagicMock, index_mock: MagicMock) -> None:
 HEAT_INDICES = ["SU", "TR", "WSDI", "TG90p", "TN90p", "TX90p", "TXx", "TNx", "CSU"]
 
 
-@pytest.mark.slow()
+@pytest.mark.slow
 class TestIntegration:
     """
     Integration tests.
@@ -282,7 +282,7 @@ def test_index_su__djf_cf_time(self) -> None:
             out_file=self.OUTPUT_FILE,
             slice_mode=FrequencyRegistry.DJF,
         )
-        np.testing.assert_array_equal(res.SU.isel(time=0), np.NAN)
+        np.testing.assert_array_equal(res.SU.isel(time=0), np.nan)
         np.testing.assert_array_equal(res.SU.isel(time=1), 0)
         # "+ 1" because DJF sampling create a december month with nans before first year
         np.testing.assert_array_equal(
diff --git a/tests/test_rechunk.py b/tests/test_rechunk.py
index 11acc4f9..e666d3db 100644
--- a/tests/test_rechunk.py
+++ b/tests/test_rechunk.py
@@ -6,6 +6,7 @@
 import pandas as pd
 import pytest
 import xarray as xr
+
 from icclim import create_optimized_zarr_store
 from icclim._core.constants import UNITS_KEY
 from icclim.exception import InvalidIcclimArgumentError
diff --git a/tests/test_threshold.py b/tests/test_threshold.py
index bc592472..168b8565 100644
--- a/tests/test_threshold.py
+++ b/tests/test_threshold.py
@@ -9,6 +9,9 @@
 import pint
 import pytest
 import xarray as xr
+from xclim.core.calendar import percentile_doy
+from xclim.core.units import units as xc_units
+
 from icclim._core.constants import UNITS_KEY
 from icclim._core.generic.threshold.basic import BasicThreshold
 from icclim._core.generic.threshold.bounded import BoundedThreshold
@@ -18,8 +21,6 @@
 from icclim._core.model.operator import OperatorRegistry
 from icclim.exception import InvalidIcclimArgumentError
 from icclim.threshold.factory import build_threshold
-from xclim.core.calendar import percentile_doy
-from xclim.core.units import units as xc_units
 
 
 def test_value_error() -> None:
diff --git a/tests/test_user_index.py b/tests/test_user_index.py
index d5d1962a..6f47632e 100644
--- a/tests/test_user_index.py
+++ b/tests/test_user_index.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from xclim.core.calendar import build_climatology_bounds
+
 import icclim
 from icclim._core.constants import (
     UNITS_KEY,
@@ -7,8 +9,6 @@
     USER_INDEX_TEMPERATURE_STAMP,
 )
 from icclim._core.model.operator import OperatorRegistry
-from xclim.core.calendar import build_climatology_bounds
-
 from tests.testing_utils import stub_tas
 
 
diff --git a/tests/testing_utils.py b/tests/testing_utils.py
index da93a55b..4add35df 100644
--- a/tests/testing_utils.py
+++ b/tests/testing_utils.py
@@ -3,6 +3,7 @@
 import numpy as np
 import pandas as pd
 import xarray as xr
+
 from icclim._core.constants import UNITS_KEY
 
 VALUE_COUNT = 365 * 5 + 1  # 5 years of data (with 1 leap year)
diff --git a/tools/extract_icclim_funs.py b/tools/extract_icclim_funs.py
index b1909bdc..b46a9f06 100644
--- a/tools/extract_icclim_funs.py
+++ b/tools/extract_icclim_funs.py
@@ -27,8 +27,9 @@
 from pathlib import Path
 from typing import TYPE_CHECKING
 
-import icclim
 from docstring_parser import Docstring, DocstringParam, DocstringStyle, compose, parse
+
+import icclim
 from icclim._core.constants import NEEDS_NORMAL, QUANTILE_BASED, REFERENCE_PERIOD_INDEX
 from icclim._core.generic.threshold.percentile import PercentileThreshold
 from icclim._core.input_parsing import get_dataarray_from_dataset
@@ -47,10 +48,11 @@
 if TYPE_CHECKING:
     from collections.abc import Sequence
 
+    from xarray import DataArray, Dataset
+
     from icclim._core.generic.indicator import GenericIndicator
     from icclim._core.model.registry import Registry
     from icclim._core.model.standard_index import StandardIndex
-    from xarray import DataArray, Dataset
 
 
 QUANTILE_INDEX_FIELDS = [
@@ -281,8 +283,8 @@ def {index.name.lower()}(
 
 
 def _normal_index_placeholder(  # noqa: ANN202
-    normal: str | Sequence[str] | Dataset | DataArray,  # noqa: ARG001
-    normal_var_name: str | None = None,  # noqa: ARG001
+    normal: str | Sequence[str] | Dataset | DataArray,
+    normal_var_name: str | None = None,
 ):
     """
     Parameters