diff --git a/doc/source/overview/tutorials/alpha_s.ipynb b/doc/source/overview/tutorials/alpha_s.ipynb
index 0136fbe7e..ed949951f 100644
--- a/doc/source/overview/tutorials/alpha_s.ipynb
+++ b/doc/source/overview/tutorials/alpha_s.ipynb
@@ -48,7 +48,7 @@
     "\n",
     "# set heavy quark masses and their threshold ratios\n",
     "heavy_quark_masses = np.power([1.51, 4.92, 172.0],2)\n",
-    "thresholds_ratios = ekotypes.MatchingScales(c=1.0, b=1.0, t=1.0)\n",
+    "thresholds_ratios = np.array([1.0, 1.0, 1.0])\n",
     "\n",
     "# set (QCD,QED) perturbative order\n",
     "order = (3, 1)\n",