10_checkpoint.ipynb: Fix inverted condition in bc53e9f

The file should be removed if it exists, not if it does not.

Author: jnareb

10_checkpoint.ipynb

@@ -362,7 +362,10 @@
     {
      "data": {
       "text/plain": [
-       "['commit_graph_Stolee.df_edgelist.csv.gz                 231']"
+       "['commit_graph_Stolee-test.df_edgelist.csv.gz            236',\n",
+       " 'commit_graph_Stolee-test.df_nodedata.csv.gz            272',\n",
+       " 'commit_graph_Stolee.df_edgelist.csv.gz                 231',\n",
+       " 'commit_graph_Stolee.df_nodedata.csv.gz                 267']"
       ]
      },
      "execution_count": null,
@@ -800,8 +803,8 @@
     "_counter = 0\n",
     "\n",
     "df_filename = 'datasets/example_dataframe.csv.gz'\n",
-    "# Path(df_filename).unlink(missing_ok=True)\n",
-    "if not Path(df_filename).exists():\n",
+    "# Path(df_filename).unlink(missing_ok=True)  # requires Python 3.8 or later\n",
+    "if Path(df_filename).exists():\n",
     "    Path(df_filename).unlink()\n",
     "\n",
     "# first time it should perform computations and save, second time get from file\n",
@@ -1219,6 +1222,8 @@
       "Converted 08_reach.ipynb.\n",
       "Converted 09_git.ipynb.\n",
       "Converted 10_checkpoint.ipynb.\n",
+      "Converted 11_datasets.ipynb.\n",
+      "Converted 12_repos.ipynb.\n",
       "Converted A.09_git_explore.ipynb.\n",
       "Converted index.ipynb.\n"
      ]