Remove key from notebook example

Fix typo in notebook example

example/example.ipynb

@@ -382,7 +382,7 @@
     "    ],\n",
     "    source_db=\"ecoinvent 3.9.1 cutoff\", # <-- name of the database in the BW2 project. Must be a string.\n",
     "    source_version=\"3.9\", # <-- version of ecoinvent. Can be \"3.5\", \"3.6\", \"3.7\" or \"3.8\". Must be a string.\n",
-    "    key=\"tUePmX_S5B8ieZkkM7WUU2CnO8SmShwmAeWK9x2rTFo=\",\n",
+    "    key=\"xxxx\", # ask premise's maintainers for a key\n",
     ")\n",
     "\n",
     "ndb.create_datapackage(\n",
@@ -426,7 +426,7 @@
    "id": "925b92d4-82c6-4943-aa80-a7022717f722",
    "metadata": {},
    "source": [
-    "When working with IAM/ESM, the focus s in the **total** quantity (e.g., electricity production, transport, etc.) coming from the IAM/ESM output and not on our examination of the supply chain as provided by LCA. To avoid double counting, we need to identify activities modeled by the IAM/ESM and set their inputs to all activities to zero. \n",
+    "When working with IAM/ESM, the focus is on the **total** quantity (e.g., electricity production, transport, etc.) coming from the IAM/ESM output and not on our examination of the supply chain as provided by LCA. To avoid double counting, we need to identify activities modeled by the IAM/ESM and set their inputs to all activities to zero.\n",
     "\n",
     "`pathways` allows users to select the categories to be considered in the double-counting adjustment. The predefined categories are illustrated below:"
    ]