add import csv to solution notebook

Mission267Solutions.ipynb

@@ -17,6 +17,7 @@
     "from datetime import datetime\n",
     "import json\n",
     "import io\n",
+    "import csv\n",
     "import string\n",
     "\n",
     "from pipeline import build_csv, Pipeline\n",
@@ -115,7 +116,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.2"
+   "version": "3.8.3"
   }
  },
  "nbformat": 4,