diff --git a/Rethinking_2/Chp_08.ipynb b/Rethinking_2/Chp_08.ipynb
index 6067927..c8d1bbb 100644
--- a/Rethinking_2/Chp_08.ipynb
+++ b/Rethinking_2/Chp_08.ipynb
@@ -576,9 +576,9 @@
     }
    ],
    "source": [
-    "coords = {'continent':cont_codes}\n",
+    "coords = {\"continent\": cont_codes}\n",
     "with pm.Model(coords=coords) as m_8_2:\n",
-    "    a = pm.Normal(\"a\", 1, 0.1, dims='continent')\n",
+    "    a = pm.Normal(\"a\", 1, 0.1, dims=\"continent\")\n",
     "    b = pm.Normal(\"b\", 0, 0.3)\n",
     "\n",
     "    mu = a[np.array(cont_idx)] + b * (dd[\"rugged_std\"].values - 0.215)\n",
@@ -967,8 +967,8 @@
    ],
    "source": [
     "with pm.Model(coords=coords) as m_8_3:\n",
-    "    a = pm.Normal(\"a\", 1, 0.1, dims='continent')\n",
-    "    b = pm.Normal(\"b\", 0, 0.3, dims='continent')\n",
+    "    a = pm.Normal(\"a\", 1, 0.1, dims=\"continent\")\n",
+    "    b = pm.Normal(\"b\", 0, 0.3, dims=\"continent\")\n",
     "\n",
     "    mu = a[np.array(cont_idx)] + b[np.array(cont_idx)] * (dd[\"rugged_std\"].values - 0.215)\n",
     "    sigma = pm.Exponential(\"sigma\", 1)\n",
diff --git a/Rethinking_2/Chp_09.ipynb b/Rethinking_2/Chp_09.ipynb
index 6717ce9..30f31fb 100644
--- a/Rethinking_2/Chp_09.ipynb
+++ b/Rethinking_2/Chp_09.ipynb
@@ -651,10 +651,10 @@
    "source": [
     "cont_idx, cont_codes = pd.factorize(dd[\"cont_africa\"])\n",
     "\n",
-    "coords = {\"continent\":cont_codes}\n",
+    "coords = {\"continent\": cont_codes}\n",
     "with pm.Model(coords=coords) as m_8_3:\n",
-    "    a = pm.Normal(\"a\", 1, 0.2, dims = \"continent\")\n",
-    "    b = pm.Normal(\"b\", 0, 0.3, dims = \"continent\")\n",
+    "    a = pm.Normal(\"a\", 1, 0.2, dims=\"continent\")\n",
+    "    b = pm.Normal(\"b\", 0, 0.3, dims=\"continent\")\n",
     "\n",
     "    mu = a[np.array(cont_idx)] + b[np.array(cont_idx)] * (dd[\"rugged_std\"].values - 0.215)\n",
     "    sigma = pm.Exponential(\"sigma\", 1)\n",