diff --git a/examples/07_fews.ipynb b/examples/07_fews.ipynb
index d4e5d248..98b28f85 100644
--- a/examples/07_fews.ipynb
+++ b/examples/07_fews.ipynb
@@ -72,9 +72,9 @@
    "outputs": [],
    "source": [
     "# download test file\n",
-    "if not os.path.exists('./fewsdata'):\n",
-    "    os.mkdir('./fewsdata')\n",
-    "xml_file_url = 'https://raw.githubusercontent.com/ArtesiaWater/hydropandas/refs/heads/master/tests/data/2019-FEWS-test/test_wsvv_fews.xml'\n",
+    "if not os.path.exists(\"./fewsdata\"):\n",
+    "    os.mkdir(\"./fewsdata\")\n",
+    "xml_file_url = \"https://raw.githubusercontent.com/ArtesiaWater/hydropandas/refs/heads/master/tests/data/2019-FEWS-test/test_wsvv_fews.xml\"\n",
     "r = requests.get(xml_file_url)\n",
     "with open(\"./fewsdata/test_wsvv_fews.xml\", \"w+\") as f:\n",
     "    f.write(r.text)"
@@ -200,7 +200,7 @@
    ],
    "source": [
     "# read a single xml file\n",
-    "fname = './fewsdata/test_wsvv_fews.xml'\n",
+    "fname = \"./fewsdata/test_wsvv_fews.xml\"\n",
     "oc = hpd.read_fews(fname, ObsClass=hpd.MeteoObs)\n",
     "oc"
    ]
@@ -240,9 +240,13 @@
    ],
    "source": [
     "# plot the measurements\n",
-    "f, axes = plt.subplots(2,1, figsize=(10, 6), sharex=True)\n",
-    "oc.get_obs('FEWS_RADAR_241_P.radar.h')['value'].plot(ax=axes[0], marker='.', legend=True, ylabel='P [mm/d]')\n",
-    "oc.get_obs('FEWS_RADAR_241_Eact.d')['value'].plot(ax=axes[1], marker='.', legend=True, ylabel='Eact [mm/d]')\n"
+    "f, axes = plt.subplots(2, 1, figsize=(10, 6), sharex=True)\n",
+    "oc.get_obs(\"FEWS_RADAR_241_P.radar.h\")[\"value\"].plot(\n",
+    "    ax=axes[0], marker=\".\", legend=True, ylabel=\"P [mm/d]\"\n",
+    ")\n",
+    "oc.get_obs(\"FEWS_RADAR_241_Eact.d\")[\"value\"].plot(\n",
+    "    ax=axes[1], marker=\".\", legend=True, ylabel=\"Eact [mm/d]\"\n",
+    ")"
    ]
   },
   {
@@ -261,7 +265,7 @@
    "outputs": [],
    "source": [
     "# download zip directory\n",
-    "zip_file_url = 'https://github.com/ArtesiaWater/hydropandas/raw/refs/heads/master/tests/data/2019-FEWS-test/WaalenBurg_201810-20190215_prod.zip'\n",
+    "zip_file_url = \"https://github.com/ArtesiaWater/hydropandas/raw/refs/heads/master/tests/data/2019-FEWS-test/WaalenBurg_201810-20190215_prod.zip\"\n",
     "r = requests.get(zip_file_url)\n",
     "with open(\"./fewsdata/WaalenBurg_201810-20190215_prod.zip\", \"wb\") as f:\n",
     "    f.write(r.content)"
@@ -403,7 +407,7 @@
    ],
    "source": [
     "# read a zipfile\n",
-    "fdir = './fewsdata/WaalenBurg_201810-20190215_prod.zip'\n",
+    "fdir = \"./fewsdata/WaalenBurg_201810-20190215_prod.zip\"\n",
     "oc = hpd.read_fews(fdir)\n",
     "oc"
    ]
@@ -436,9 +440,13 @@
    ],
    "source": [
     "# plot the measurements\n",
-    "f, ax= plt.subplots(figsize=(10, 3))\n",
-    "oc.get_obs('MPN-N-1_H.meting')['value'].plot(ax=ax, marker='.', legend=True, ylabel='m NAP')\n",
-    "oc.get_obs('MPN-N-2_H.meting')['value'].plot(ax=ax, marker='.', legend=True, ylabel='m NAP')\n"
+    "f, ax = plt.subplots(figsize=(10, 3))\n",
+    "oc.get_obs(\"MPN-N-1_H.meting\")[\"value\"].plot(\n",
+    "    ax=ax, marker=\".\", legend=True, ylabel=\"m NAP\"\n",
+    ")\n",
+    "oc.get_obs(\"MPN-N-2_H.meting\")[\"value\"].plot(\n",
+    "    ax=ax, marker=\".\", legend=True, ylabel=\"m NAP\"\n",
+    ")"
    ]
   },
   {
@@ -462,22 +470,24 @@
    "outputs": [],
    "source": [
     "# put here the URL of your fews database\n",
-    "fews_db_url = \"\" # enter fews database url here\n",
-    "location_id = \"\" # enter location id here\n",
+    "fews_db_url = \"\"  # enter fews database url here\n",
+    "location_id = \"\"  # enter location id here\n",
     "\n",
     "# read as observation objects\n",
-    "params = {\"locationIds\": location_id,\n",
-    "          \"documentVersion\": \"1.26\",\n",
-    "          \"documentFormat\": \"PI_XML\"}\n",
+    "params = {\n",
+    "    \"locationIds\": location_id,\n",
+    "    \"documentVersion\": \"1.26\",\n",
+    "    \"documentFormat\": \"PI_XML\",\n",
+    "}\n",
     "\n",
     "r = requests.get(fews_db_url, params=params, verify=True)\n",
     "xmlstring = r.text\n",
     "\n",
     "oc = hpd.ObsCollection.from_fews_xml(\n",
-    "        xmlstring=xmlstr,\n",
-    "        ObsClass=hpd.Obs,\n",
-    "        low_memory=False,\n",
-    "    )\n",
+    "    xmlstring=xmlstr,\n",
+    "    ObsClass=hpd.Obs,\n",
+    "    low_memory=False,\n",
+    ")\n",
     "\n",
     "oc"
    ]