navis exercise 2: fix meta data column issue

exercises/navis/navis_exercise_2.ipynb

@@ -102,8 +102,12 @@
     "\n",
     "meta = pd.read_csv(\"~/Downloads/20200711_patchseq_metadata_mouse.csv\")\n",
     "\n",
-    "# Strangely, the last column with the transcriptomic (\"t\") types has no name - let's fix that:\n",
-    "meta.columns = list(meta.columns[:-1]) + [\"t_type\"]\n",
+    "# Important note: if you downloaded the meta data CSV from the link in the paper, the name of the last column\n",
+    "# which contains the T-type is missing. You can add it manually by running the following line:\n",
+    "# meta.columns = list(meta.columns[:-1]) + [\"T-type Label\"]\n",
+    "\n",
+    "# Let's rename the \"T-type Label\" column to just \"t_type\" to make our lives a bit easier\n",
+    "meta = meta.rename(columns={\"T-type Label\": \"t_type\"})\n",
     "\n",
     "meta.head()"
    ]