diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index efdb4a4..ea7e671 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,10 +21,8 @@ jobs:
     defaults:
       run:
         shell: bash
-
     steps:
 
-    # check out repo
     - name: Checkout repo
       uses: actions/checkout@v3
 
@@ -45,19 +43,16 @@ jobs:
       run: |
         python -c "import modflowapi; print(modflowapi.__version__)"
 
-
   lint:
     name: lint
     runs-on: ubuntu-latest
+    if: github.event_name != 'schedule'
     strategy:
       fail-fast: false
     defaults:
       run:
         shell: bash
-
-    if: github.event_name != 'schedule'
     steps:
-    # check out repo
     - name: Checkout repo
       uses: actions/checkout@v3
 
@@ -78,20 +73,11 @@ jobs:
         python -m pip install --upgrade pip
         pip install -e .[lint]
 
-    - name: Run black
-      run: |
-        echo "if black check fails run"
-        echo "  black ./modflowapi"
-        echo "and then commit the changes."
-        black --check ./modflowapi
-
-    - name: Run flake8
-      run: |
-        flake8 --count --show-source --exit-zero ./modflowapi
+    - name: Lint
+      run: ruff check .
 
-    - name: Run pylint
-      run: |
-        pylint --jobs=2 --errors-only --exit-zero ./modflowapi
+    - name: Check format
+      run: ruff format . --check
 
   autotest_extensions:
     name: modflowapi extensions autotests
@@ -105,9 +91,7 @@ jobs:
     defaults:
       run:
         shell: bash
-
     steps:
-      # check out repo
       - name: Checkout repo
         uses: actions/checkout@v3
 
@@ -148,9 +132,7 @@ jobs:
     defaults:
       run:
         shell: bash
-
     steps:
-      # check out repo
       - name: Checkout repo
         uses: actions/checkout@v3
 
@@ -192,9 +174,7 @@ jobs:
     defaults:
       run:
         shell: bash
-
     steps:
-      # check out repo
       - name: Checkout repo
         uses: actions/checkout@v3
 
@@ -212,12 +192,12 @@ jobs:
           pip install git+https://git@github.com/MODFLOW-USGS/modflow-devtools@develop
           pip install .[test]
 
-      - name: Install modflow executables
+      - name: Install modflow6 nightly build
         uses: modflowpy/install-modflow-action@v1
         with:
           path: ${{ github.workspace }}/autotest
           repo: modflow6-nightly-build
-
+      
       - name: Run autotests
         working-directory: ./autotest
         shell: bash -l {0}
diff --git a/.gitignore b/.gitignore
index a0b56cf..6a6e2e1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -130,3 +130,8 @@ dmypy.json
 
 # pycharm
 .idea/
+
+# library files
+**.dll
+**.so
+**.dylib
\ No newline at end of file
diff --git a/autotest/conftest.py b/autotest/conftest.py
index e417e43..d059061 100644
--- a/autotest/conftest.py
+++ b/autotest/conftest.py
@@ -6,6 +6,11 @@
 import pytest
 from filelock import FileLock
 
+from modflow_devtools.download import download_and_unzip
+
+# import modflow-devtools fixtures
+pytest_plugins = ["modflow_devtools.fixtures"]
+
 
 __mf6_examples = "mf6_examples"
 __mf6_examples_path = Path(gettempdir()) / __mf6_examples
@@ -13,9 +18,6 @@
 
 
 def get_mf6_examples_path() -> Path:
-    pytest.importorskip("modflow_devtools")
-    from modflow_devtools.download import download_and_unzip
-
     # use file lock so mf6 distribution is downloaded once,
     # even when tests are run in parallel with pytest-xdist
     __mf6_examples_lock.acquire()
@@ -95,45 +97,3 @@ def simulation_name_from_model_namfiles(mnams):
         metafunc.parametrize(
             key, simulations, ids=simulation_name_from_model_namfiles
         )
-
-
-@pytest.fixture(scope="function")
-def tmpdir(tmpdir_factory, request) -> Path:
-    node = (
-        request.node.name.replace("/", "_")
-        .replace("\\", "_")
-        .replace(":", "_")
-    )
-    temp = Path(tmpdir_factory.mktemp(node))
-    yield Path(temp)
-
-    keep = request.config.getoption("--keep")
-    if keep:
-        copytree(temp, Path(keep) / temp.name)
-
-    keep_failed = request.config.getoption("--keep-failed")
-    if keep_failed and request.node.rep_call.failed:
-        copytree(temp, Path(keep_failed) / temp.name)
-
-
-def pytest_addoption(parser):
-    parser.addoption(
-        "-K",
-        "--keep",
-        action="store",
-        default=None,
-        help="Move the contents of temporary test directories to correspondingly named subdirectories at the given "
-        "location after tests complete. This option can be used to exclude test results from automatic cleanup, "
-        "e.g. for manual inspection. The provided path is created if it does not already exist. An error is "
-        "thrown if any matching files already exist.",
-    )
-
-    parser.addoption(
-        "--keep-failed",
-        action="store",
-        default=None,
-        help="Move the contents of temporary test directories to correspondingly named subdirectories at the given "
-        "location if the test case fails. This option automatically saves the outputs of failed tests in the "
-        "given location. The path is created if it doesn't already exist. An error is thrown if files with the "
-        "same names already exist in the given location.",
-    )
diff --git a/autotest/test_interface.py b/autotest/test_interface.py
index 5027218..8119a5f 100644
--- a/autotest/test_interface.py
+++ b/autotest/test_interface.py
@@ -11,7 +11,6 @@
     AdvancedPackage,
     ArrayPackage,
     ListPackage,
-    pkgvars,
 )
 
 data_pth = Path("../examples/data")
@@ -20,7 +19,11 @@
 so = "libmf6" + (
     ".so"
     if os == "Linux"
-    else ".dylib" if os == "Darwin" else ".dll" if os == "Windows" else None
+    else ".dylib"
+    if os == "Darwin"
+    else ".dll"
+    if os == "Windows"
+    else None
 )
 if so is None:
     pytest.skip("Unsupported operating system", allow_module_level=True)
@@ -28,27 +31,27 @@
 
 @pytest.mark.parametrize("use_str", [True, False])
 def test_ctor_finds_libmf6_by_name(use_str):
-    api = ModflowApi(so if use_str else Path(so))
+    ModflowApi(so if use_str else Path(so))
 
 
 @pytest.mark.parametrize("use_str", [True, False])
-def test_ctor_finds_libmf6_by_relpath(tmpdir, use_str):
-    shutil.copy(so, tmpdir)
-    inner = tmpdir / "inner"
+def test_ctor_finds_libmf6_by_relpath(function_tmpdir, use_str):
+    shutil.copy(so, function_tmpdir)
+    inner = function_tmpdir / "inner"
     inner.mkdir()
     with set_dir(inner):
         so_path = f"../{so}"
-        api = ModflowApi(so_path if use_str else Path(so_path))
+        ModflowApi(so_path if use_str else Path(so_path))
 
 
 @pytest.mark.parametrize("use_str", [True, False])
-def test_ctor_finds_libmf6_by_abspath(tmpdir, use_str):
-    shutil.copy(so, tmpdir)
-    so_path = tmpdir / so
-    api = ModflowApi(str(so_path) if use_str else so_path)
+def test_ctor_finds_libmf6_by_abspath(function_tmpdir, use_str):
+    shutil.copy(so, function_tmpdir)
+    so_path = function_tmpdir / so
+    ModflowApi(str(so_path) if use_str else so_path)
 
 
-def test_dis_model(tmpdir):
+def test_dis_model(function_tmpdir):
     def callback(sim, step):
         """
         Callback function
@@ -134,7 +137,7 @@ def callback(sim, step):
 
     name = "dis_model"
     sim_pth = data_pth / name
-    test_pth = tmpdir / name
+    test_pth = function_tmpdir / name
     shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
     try:
@@ -143,7 +146,7 @@ def callback(sim, step):
         raise Exception(e)
 
 
-def test_disv_model(tmpdir):
+def test_disv_model(function_tmpdir):
     def callback(sim, step):
         """
         Callback function
@@ -220,7 +223,7 @@ def callback(sim, step):
 
     name = "disv_model"
     sim_pth = data_pth / name
-    test_pth = tmpdir / name
+    test_pth = function_tmpdir / name
     shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
     try:
@@ -229,7 +232,7 @@ def callback(sim, step):
         raise Exception(e)
 
 
-def test_disu_model(tmpdir):
+def test_disu_model(function_tmpdir):
     def callback(sim, step):
         """
         Callback function
@@ -300,7 +303,7 @@ def callback(sim, step):
 
     name = "disu_model"
     sim_pth = data_pth / name
-    test_pth = tmpdir / name
+    test_pth = function_tmpdir / name
     shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
     try:
@@ -309,7 +312,7 @@ def callback(sim, step):
         raise Exception(e)
 
 
-def test_two_models(tmpdir):
+def test_two_models(function_tmpdir):
     def callback(sim, step):
         """
         Callback function
@@ -326,7 +329,7 @@ def callback(sim, step):
 
     name = "two_models"
     sim_pth = data_pth / name
-    test_pth = tmpdir / name
+    test_pth = function_tmpdir / name
     shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
     try:
@@ -335,7 +338,7 @@ def callback(sim, step):
         raise Exception(e)
 
 
-def test_ats_model(tmpdir):
+def test_ats_model(function_tmpdir):
     def callback(sim, step):
         if step == Callbacks.stress_period_start:
             if sim.kper == 0 and sim.kstp == 0:
@@ -350,7 +353,7 @@ def callback(sim, step):
 
         name = "ats0"
         sim_pth = data_pth / name
-        test_pth = tmpdir / name
+        test_pth = function_tmpdir / name
         shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
         try:
@@ -359,7 +362,7 @@ def callback(sim, step):
             raise Exception(e)
 
 
-def test_rhs_hcof_advanced(tmpdir):
+def test_rhs_hcof_advanced(function_tmpdir):
     def callback(sim, step):
         model = sim.test_model
         if step == Callbacks.timestep_start:
@@ -410,7 +413,7 @@ def callback(sim, step):
 
     name = "dis_model"
     sim_pth = data_pth / name
-    test_pth = tmpdir / name
+    test_pth = function_tmpdir / name
     shutil.copytree(sim_pth, test_pth, dirs_exist_ok=True)
 
     try:
diff --git a/autotest/test_mf6_examples.py b/autotest/test_mf6_examples.py
index 8ed392b..36e1647 100644
--- a/autotest/test_mf6_examples.py
+++ b/autotest/test_mf6_examples.py
@@ -9,14 +9,14 @@
 dll = "libmf6"
 
 
-def test_mf6_example_simulations(tmpdir, mf6_example_namfiles):
+def test_mf6_example_simulations(function_tmpdir, mf6_example_namfiles):
     """
     MF6 examples parametrized by simulation. `mf6_example_namfiles` is a list
     of models to run in order provided. Coupled models share the same tempdir
 
     Parameters
     ----------
-    tmpdir: function-scoped temporary directory fixture
+    function_tmpdir: function-scoped temporary directory fixture
     mf6_example_namfiles: ordered list of namfiles for 1+ coupled models
     """
     if len(mf6_example_namfiles) == 0:
@@ -24,10 +24,11 @@ def test_mf6_example_simulations(tmpdir, mf6_example_namfiles):
     namfile = Path(mf6_example_namfiles[0])
 
     nested = is_nested(namfile)
-    tmpdir = Path(tmpdir / "workspace")
+    function_tmpdir = Path(function_tmpdir / "workspace")
 
     copytree(
-        src=namfile.parent.parent if nested else namfile.parent, dst=tmpdir
+        src=namfile.parent.parent if nested else namfile.parent,
+        dst=function_tmpdir,
     )
 
     def callback(sim, step):
@@ -37,12 +38,15 @@ def run_models():
         # run models in order received (should be alphabetical, so gwf precedes gwt)
         for namfile in mf6_example_namfiles:
             namfile_path = Path(namfile).resolve()
-            namfile_name = namfile_path.name
             model_path = namfile_path.parent
 
             # working directory must be named according to the name file's parent (e.g.
             # 'mf6gwf') because coupled models refer to each other with relative paths
-            wrkdir = Path(tmpdir / model_path.name) if nested else tmpdir
+            wrkdir = (
+                Path(function_tmpdir / model_path.name)
+                if nested
+                else function_tmpdir
+            )
             try:
                 run_simulation(dll, wrkdir, callback, verbose=True)
             except Exception as e:
diff --git a/examples/notebooks/Head_Monitor_Example.ipynb b/examples/notebooks/Head_Monitor_Example.ipynb
index 91a2219..20ea830 100644
--- a/examples/notebooks/Head_Monitor_Example.ipynb
+++ b/examples/notebooks/Head_Monitor_Example.ipynb
@@ -17,11 +17,14 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from IPython.display import clear_output, display  # remove this import if adapted to python script\n",
+    "from IPython.display import (\n",
+    "    clear_output,\n",
+    "    display,\n",
+    ")  # remove this import if adapted to python script\n",
     "\n",
     "from modflowapi import run_simulation, Callbacks\n",
     "from flopy.discretization import StructuredGrid\n",
-    "from flopy.plot import PlotMapView, styles\n",
+    "from flopy.plot import PlotMapView\n",
     "from pathlib import Path\n",
     "import numpy as np\n",
     "import matplotlib.pyplot as plt"
@@ -47,12 +50,12 @@
     "class StructuredHeadMonitor:\n",
     "    \"\"\"\n",
     "    An example class that reverses the model gradient by\n",
-    "    swapping CHD boundary conditions each stress period, \n",
+    "    swapping CHD boundary conditions each stress period,\n",
     "    and monitors the head at each timestep by updating\n",
-    "    a matplotlib plot. This class could be adapted to \n",
+    "    a matplotlib plot. This class could be adapted to\n",
     "    be used as a head monitor to observe other changes\n",
     "    in the model by modifying the callback class.\n",
-    "    \n",
+    "\n",
     "    Parameters\n",
     "    ----------\n",
     "    layer: int\n",
@@ -77,7 +80,7 @@
     "    def build_modelgrid(self, ml):\n",
     "        \"\"\"\n",
     "        Method to update the matplotlib plot\n",
-    "        \n",
+    "\n",
     "        Parameters\n",
     "        ----------\n",
     "        ml : ApiModel\n",
@@ -89,11 +92,7 @@
     "        botm = ml.dis.bot.values\n",
     "        idomain = ml.dis.idomain.values\n",
     "        self.modelgrid = StructuredGrid(\n",
-    "            delc=delc,\n",
-    "            delr=delr,\n",
-    "            top=top,\n",
-    "            botm=botm,\n",
-    "            idomain=idomain\n",
+    "            delc=delc, delr=delr, top=top, botm=botm, idomain=idomain\n",
     "        )\n",
     "\n",
     "    def initialize_plot(self):\n",
@@ -103,7 +102,9 @@
     "        fig, ax = plt.subplots(figsize=(8, 8))\n",
     "        self.fig = fig\n",
     "        self.ax = ax\n",
-    "        self.pmv = PlotMapView(modelgrid=self.modelgrid, ax=ax, layer=self.layer)\n",
+    "        self.pmv = PlotMapView(\n",
+    "            modelgrid=self.modelgrid, ax=ax, layer=self.layer\n",
+    "        )\n",
     "        grid = self.pmv.plot_grid()\n",
     "        idm = self.pmv.plot_inactive()\n",
     "        initial = np.full(self.modelgrid.shape, np.nan)\n",
@@ -113,7 +114,7 @@
     "    def update_plot(self, ml):\n",
     "        \"\"\"\n",
     "        Method to update the matplotlib plot\n",
-    "        \n",
+    "\n",
     "        Parameters\n",
     "        ----------\n",
     "        ml : ApiModel\n",
@@ -124,16 +125,16 @@
     "        grid = self.pmv.plot_grid()\n",
     "        idm = self.pmv.plot_inactive()\n",
     "        self.pc = self.pmv.plot_array(heads, vmin=self.vmin, vmax=self.vmax)\n",
-    "        \n",
+    "\n",
     "        # only applicable to jupyter notebooks, remove these two lines in python scipt\n",
-    "        display(self.fig)  \n",
+    "        display(self.fig)\n",
     "        if ml.kper == (ml.nper - 1) and ml.kstp == (ml.nstp - 1):\n",
     "            pass\n",
     "        else:\n",
-    "            clear_output(wait = True)  \n",
-    "        \n",
-    "        # the pause time can be reduced if adapted in python script \n",
-    "        plt.pause(0.1)  \n",
+    "            clear_output(wait=True)\n",
+    "\n",
+    "        # the pause time can be reduced if adapted in python script\n",
+    "        plt.pause(0.1)\n",
     "\n",
     "    def callback(self, sim, callback_step):\n",
     "        \"\"\"\n",
@@ -145,7 +146,7 @@
     "        Parameters\n",
     "        ----------\n",
     "        sim : modflowapi.Simulation\n",
-    "            A simulation object for the solution group that is \n",
+    "            A simulation object for the solution group that is\n",
     "            currently being solved\n",
     "        callback_step : enumeration\n",
     "            modflowapi.Callbacks enumeration object that indicates\n",
@@ -173,7 +174,7 @@
     "\n",
     "        if callback_step == Callbacks.timestep_end:\n",
     "            ml = sim.get_model()\n",
-    "            self.update_plot(ml)\n"
+    "            self.update_plot(ml)"
    ]
   },
   {
diff --git a/examples/notebooks/MODFLOW-API_extensions_objects.ipynb b/examples/notebooks/MODFLOW-API_extensions_objects.ipynb
index 87cb991..cef3af7 100644
--- a/examples/notebooks/MODFLOW-API_extensions_objects.ipynb
+++ b/examples/notebooks/MODFLOW-API_extensions_objects.ipynb
@@ -50,7 +50,7 @@
     "    ext = \".so\"\n",
     "else:\n",
     "    ext = \".dylib\"\n",
-    "    \n",
+    "\n",
     "dll = Path(dll + ext)"
    ]
   },
@@ -191,7 +191,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "model = sim.get_model('test_model')\n",
+    "model = sim.get_model(\"test_model\")\n",
     "model"
    ]
   },
@@ -368,7 +368,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "recarray['recharge'][0] *= 100\n",
+    "recarray[\"recharge\"][0] *= 100\n",
     "rch.stress_period_data.values = recarray\n",
     "\n",
     "# show that values have been updated\n",
@@ -472,7 +472,7 @@
    "outputs": [],
    "source": [
     "recarray.resize((nbound + 1,), refcheck=False)\n",
-    "recarray[-1] = ((0, 1, 5), -20., 0, 1)\n",
+    "recarray[-1] = ((0, 1, 5), -20.0, 0, 1)\n",
     "recarray"
    ]
   },
@@ -754,11 +754,11 @@
     "    \"\"\"\n",
     "    A demonstration function that dynamically adjusts recharge\n",
     "    and pumping in a modflow-6 model through the MODFLOW-API\n",
-    "    \n",
+    "\n",
     "    Parameters\n",
     "    ----------\n",
     "    sim : modflowapi.Simulation\n",
-    "        A simulation object for the solution group that is \n",
+    "        A simulation object for the solution group that is\n",
     "        currently being solved\n",
     "    callback_step : enumeration\n",
     "        modflowapi.Callbacks enumeration object that indicates\n",
@@ -767,7 +767,7 @@
     "    ml = sim.test_model\n",
     "    if callback_step == Callbacks.initialize:\n",
     "        print(sim.models)\n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.stress_period_start:\n",
     "        # adjust recharge for stress periods 1 through 7\n",
     "        if sim.kper <= 6:\n",
@@ -775,16 +775,16 @@
     "            spd = rcha.stress_period_data\n",
     "            print(f\"updating recharge: stress_period={ml.kper}\")\n",
     "            spd[\"recharge\"] += 0.40 * sim.kper\n",
-    "        \n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.timestep_start:\n",
-    "        print(f\"updating wel flux: stress_period={ml.kper}, timestep={ml.kstp}\")\n",
+    "        print(\n",
+    "            f\"updating wel flux: stress_period={ml.kper}, timestep={ml.kstp}\"\n",
+    "        )\n",
     "        ml.wel.stress_period_data[\"q\"] -= ml.kstp * 1.5\n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.iteration_start:\n",
     "        # we can implement complex solutions to boundary conditions here!\n",
-    "        pass\n",
-    "    "
+    "        pass"
    ]
   },
   {
diff --git a/examples/notebooks/Quickstart.ipynb b/examples/notebooks/Quickstart.ipynb
index 9c6eff7..ddd7ac8 100644
--- a/examples/notebooks/Quickstart.ipynb
+++ b/examples/notebooks/Quickstart.ipynb
@@ -19,7 +19,6 @@
    "source": [
     "import modflowapi\n",
     "from modflowapi import Callbacks\n",
-    "import numpy as np\n",
     "from pathlib import Path"
    ]
   },
@@ -74,11 +73,11 @@
     "    \"\"\"\n",
     "    A demonstration function that dynamically adjusts recharge\n",
     "    and pumping in a modflow-6 model through the MODFLOW-API\n",
-    "    \n",
+    "\n",
     "    Parameters\n",
     "    ----------\n",
     "    sim : modflowapi.ApiSimulation\n",
-    "        A simulation object for the solution group that is \n",
+    "        A simulation object for the solution group that is\n",
     "        currently being solved\n",
     "    step : enumeration\n",
     "        modflowapi.Callbacks enumeration object that indicates\n",
@@ -87,7 +86,7 @@
     "    ml = sim.test_model\n",
     "    if callback_step == Callbacks.initialize:\n",
     "        print(sim.models)\n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.stress_period_start:\n",
     "        # adjust recharge for stress periods 7 through 12\n",
     "        if sim.kper <= 6:\n",
@@ -95,16 +94,16 @@
     "            spd = rcha.stress_period_data\n",
     "            print(f\"updating recharge: stress_period={ml.kper}\")\n",
     "            spd[\"recharge\"] += 0.40 * sim.kper\n",
-    "        \n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.timestep_start:\n",
-    "        print(f\"updating wel flux: stress_period={ml.kper}, timestep={ml.kstp}\")\n",
+    "        print(\n",
+    "            f\"updating wel flux: stress_period={ml.kper}, timestep={ml.kstp}\"\n",
+    "        )\n",
     "        ml.wel.stress_period_data[\"q\"] -= ml.kstp * 1.5\n",
-    "    \n",
+    "\n",
     "    if callback_step == Callbacks.iteration_start:\n",
     "        # we can implement complex solutions to boundary conditions here!\n",
-    "        pass\n",
-    "    "
+    "        pass"
    ]
   },
   {
diff --git a/modflowapi/__init__.py b/modflowapi/__init__.py
index dccdd54..0526956 100644
--- a/modflowapi/__init__.py
+++ b/modflowapi/__init__.py
@@ -1,4 +1,4 @@
-# imports
+# ruff: noqa: F401, allow imports directly from modflowapi
 from .version import __version__
 from modflowapi.modflowapi import ModflowApi
 
diff --git a/modflowapi/extensions/__init__.py b/modflowapi/extensions/__init__.py
index 9fa55e0..f7cbfa5 100644
--- a/modflowapi/extensions/__init__.py
+++ b/modflowapi/extensions/__init__.py
@@ -1,3 +1,4 @@
+# ruff: noqa: F401, allow imports directly from modflowapi.extensions
 from .apisimulation import ApiSimulation
 from .apimodel import ApiModel
 from .apiexchange import ApiExchange
diff --git a/modflowapi/extensions/apimodel.py b/modflowapi/extensions/apimodel.py
index d899d7d..e60e0da 100644
--- a/modflowapi/extensions/apimodel.py
+++ b/modflowapi/extensions/apimodel.py
@@ -366,8 +366,8 @@ def _set_node_mapping(self):
         user arrays to modflow's internal arrays
         """
         node_addr = self.mf6.get_var_address("NODES", self.name, self.dis_name)
-        nodes = self.mf6.get_value(node_addr)
-        if nodes[0] == self.size:
+        nodes = self.mf6.get_value(node_addr).item()
+        if nodes == self.size:
             nodeuser = np.arange(nodes).astype(int)
             nodereduced = np.copy(nodeuser)
         else:
diff --git a/modflowapi/extensions/apisimulation.py b/modflowapi/extensions/apisimulation.py
index 5d96dde..e71816e 100644
--- a/modflowapi/extensions/apisimulation.py
+++ b/modflowapi/extensions/apisimulation.py
@@ -52,13 +52,13 @@ def __repr__(self):
         s += f"Number of models: {len(self._models)}:\n"
         for name, obj in self._models.items():
             s += f"\t{name} : {type(obj)}\n"
-        s += f"Simulation level packages include:\n"
+        s += "Simulation level packages include:\n"
         s += f"\tSLN: {self.sln}\n"
         s += f"\tTDIS: {self.tdis}\n"
         if self.ats_active:
             s += f"\tATS: {self.ats}\n"
         if self._exchanges:
-            s += f"\tExchanges include:\n"
+            s += "\tExchanges include:\n"
             for name, exchange in self._exchanges.items():
                 f"\t\t{name}: {type(exchange)}\n"
 
diff --git a/modflowapi/extensions/runner.py b/modflowapi/extensions/runner.py
index 11e67fe..dc9e241 100644
--- a/modflowapi/extensions/runner.py
+++ b/modflowapi/extensions/runner.py
@@ -1,7 +1,5 @@
 from .. import ModflowApi
 from .apisimulation import ApiSimulation
-import pathlib
-import platform
 from enum import Enum
 
 
diff --git a/pyproject.toml b/pyproject.toml
index 9136c6e..9bc110c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -48,10 +48,7 @@ test = [
     "pytest-xdist",
 ]
 lint = [
-    "black",
-    "flake8",
-    "isort",
-    "pylint",
+    "ruff",
 ]
 
 [project.urls]
@@ -64,6 +61,21 @@ version = {attr = "modflowapi.version.__version__"}
 [tool.setuptools.packages.find]
 include = ["modflowapi", "modflowapi.*"]
 
-[tool.black]
+[tool.ruff]
+target-version = "py38"
 line-length = 79
-target_version = ["py37"]
+include = [
+    "pyproject.toml",
+    "modflowapi/**/*.py",
+    "autotest/**/*.py",
+    "examples/**/*.py",
+    "scripts/**/*.py",
+]
+extend-include = [
+    "examples/**/*.ipynb"
+]
+
+[tool.ruff.lint]
+ignore = [
+    "F841" # local variable assigned but never used
+]
\ No newline at end of file
diff --git a/scripts/update_version.py b/scripts/update_version.py
index bf3cc9f..9e90e6b 100644
--- a/scripts/update_version.py
+++ b/scripts/update_version.py
@@ -71,7 +71,7 @@ def update_version(
     finally:
         try:
             lock_path.unlink()
-        except:
+        except FileNotFoundError:
             pass