Added note on dense argument in docs

docs/source/notebooks/benchmark.ipynb

@@ -1065,7 +1065,15 @@
     "and we can optionaly change their parametters too (for more information check the `decouple` function).\n",
     "\n",
     "To run the benchmark pipeline, we need input molecular data (`mat`), its associated metadata (`obs`) with the name of the\n",
-    "column where the perturbed regulators are (`perturb`), and which direction the pertrubations are (`sign`, positive or negative)."
+    "column where the perturbed regulators are (`perturb`), and which direction the pertrubations are (`sign`, positive or negative).\n",
+    "\n",
+    "<div class=\"alert alert-info\">\n",
+    "\n",
+    "**Note**\n",
+    "    \n",
+    "Note that if you want to ignore missing values in the input `mat` (denoted as zeros), you can add the parameter `'dense': True` to `decouple_kws`.\n",
+    "\n",
+    "</div>"
    ]
   },
   {