[pre-commit.ci] auto fixes from pre-commit.com hooks

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Author: pre-commit-ci[bot]

docs/user_guide/examples/tutorial_diffusion.ipynb

@@ -195,7 +195,7 @@
     "ds = simple_UV_dataset(dims=(1, 1, Ny, 1), mesh=\"flat\").isel(time=0, depth=0)\n",
     "ds[\"lat\"][:] = np.linspace(-0.01, 1.01, Ny)\n",
     "ds[\"lon\"][:] = np.ones(len(ds.XG))\n",
-    "ds[\"Kh_meridional\"] = ([\"YG\",\"XG\"], Kh_meridional[:, None])\n",
+    "ds[\"Kh_meridional\"] = ([\"YG\", \"XG\"], Kh_meridional[:, None])\n",
     "ds"
    ]
   },
@@ -497,6 +497,7 @@
    "source": [
     "fieldset = parcels.FieldSet.from_copernicusmarine(ds_fields)\n",
     "\n",
+    "\n",
     "def degree_lat_to_meter(d):\n",
     "    return d * 1000.0 * 1.852 * 60.0\n",
     "\n",