edit grammar in sets

Author: Rise Riyo

part-4.ipynb

@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:2e85a1190fdc5f2a5f5567835384cdf4dc4a717102ea921578a4ee8c4d69eccc"
+  "signature": "sha256:2370e04209148fe9960fb427f1cf48a0972c89329bf5505554ad65ea1f41413d"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -360,8 +360,7 @@
      ],
      "language": "python",
      "metadata": {},
-     "outputs": [],
-     "prompt_number": 39
+     "outputs": []
     },
     {
      "cell_type": "code",
@@ -371,17 +370,7 @@
      ],
      "language": "python",
      "metadata": {},
-     "outputs": [
-      {
-       "metadata": {},
-       "output_type": "pyout",
-       "prompt_number": 40,
-       "text": [
-        "'the dog ate the burrito green'"
-       ]
-      }
-     ],
-     "prompt_number": 40
+     "outputs": []
     },
     {
      "cell_type": "code",
@@ -418,7 +407,7 @@
       "\n",
       "Sets are unordered collections of distinct items.  Lists can have duplicates of the same item, but sets only store one copy.\n",
       "\n",
-      "Let's say we want to make a roster of people who have RSVPed to our birthday party.  If someone RSVPs twice we don't want them show up in our roster twice.  Let's use a set!"
+      "Let's say we want to make a roster of people who have RSVPed to our birthday party.  If someone RSVPs twice, we don't want them showing up in our roster twice.  Let's use a set!"
      ]
     },
     {