Small edits to Lab01, mostly just typos/grammar.

Also made some edits to block quotes to work around this bug in markdown-it-py:
executablebooks/markdown-it-py#185

Author: fperez

lab/lab01.ipynb

@@ -20,7 +20,7 @@
     "\n",
     "1. **Setting up GitHub Account.** If you want to learn more about how to work with GitHub and how GitHub internally works, we recommend you to take a look to [The curious coder’s guide to git](https://matthew-brett.github.io/curious-git/). After we all have a GitHub account, we will ask you to complete this [form](https://docs.google.com/forms/d/1LMPPklVx6l7qdcBppK0jxpBWJv-95imkCMoaZxjl6_A/edit) so we can add you to GitHub Classroom. \n",
     "\n",
-    "1. **Warming up with Python.** We will follow the Python tutorial wrote by Jake VanderPlas, [A Whirlwind Tour of Python](https://jakevdp.github.io/WhirlwindTourOfPython/).\n",
+    "1. **Warming up with Python.** We will follow the Python tutorial written by Jake VanderPlas, [A Whirlwind Tour of Python](https://jakevdp.github.io/WhirlwindTourOfPython).\n",
     "    \n",
     "1. **Debugging in Python/iPython.**\n",
     "    1. Debuggin with [pdb](https://docs.python.org/3/library/pdb.html) \n",
@@ -34,55 +34,7 @@
     "- Interpreted instead of compiled\n",
     "- Clean syntax\n",
     "- Object oriented (attributes + methods), convenient language constructs\n",
-    "- Variables are pointers (speed and memory efficient)"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 46,
-   "id": "de3d095b-813e-4fa1-8fdf-e4741f9a44e0",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "171\n"
-     ]
-    }
-   ],
-   "source": [
-    "import sys\n",
-    "\n",
-    "print(sys.getrefcount(255))"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 48,
-   "id": "23946485-73ed-44fd-929e-371ba5de4a55",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "x1 = 255"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 49,
-   "id": "300b5087-477e-464c-a66c-1d68b3e70815",
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "172\n"
-     ]
-    }
-   ],
-   "source": [
-    "print(sys.getrefcount(255))"
+    "- Variables can access large data structures by reference, without making a copy (speed and memory efficient)."
    ]
   },
   {
@@ -119,7 +71,7 @@
     "\n",
     ">\n",
     "> Once you have your GitHub account, please take a few minutes to complete this form.  \n",
-    ">"
+    ">\n"
    ]
   },
   {
@@ -172,7 +124,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "### .... [To do during the lab] Construct the following funtion\n",
+    "### .... [To do during the lab] Construct the following function\n",
     "\n",
     "\n",
     "from math import gcd      # we import the great common divisor function from math\n",
@@ -403,7 +355,7 @@
    "source": [
     "### 2.2. Errors and Exceptions\n",
     "\n",
-    "Different kind of errors that occur as we write code include syntax, runtime and semantic errors. Specially for runtime errors, Python give us a clue about what kind or error may happened during the execution of our code. For example,"
+    "Different kinds of errors that occur as we write code include syntax, runtime and semantic errors. Specially for runtime errors, Python give us a clue about what kind or error may happened during the execution of our code. For example,"
    ]
   },
   {
@@ -498,17 +450,26 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "id": "ca2d920e-587d-4e9e-a0ee-45da2ddbe92d",
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "I was here\n",
+      "Something wrong happened\n"
+     ]
+    }
+   ],
    "source": [
     "try:\n",
     "    print(\"I was here\")\n",
     "    a / b\n",
     "    print(\"Was I here?\")\n",
     "except: \n",
-    "    print(\"Something wrong happen\")"
+    "    print(\"Something wrong happened\")"
    ]
   },
   {
@@ -580,9 +541,9 @@
    "id": "e8992735-a9c6-4656-81c4-f766362f33a2",
    "metadata": {},
    "source": [
-    "## 3. Debuggin in Jupyter \n",
+    "## 3. Debugging in Jupyter \n",
     "\n",
-    "Jupyter allow us to do post-mortem debugging with the `%debug` command. This is a basic pdb debugger."
+    "Jupyter allow us to do post-mortem debugging with the `%debug` command. This is a wrapper around the basic [pdb debugger](https://docs.python.org/3/library/pdb.html) that ships with the Python language."
    ]
   },
   {
@@ -714,7 +675,7 @@
     "\n",
     ">\n",
     "> *A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away.*\n",
-    ">"
+    ">\n"
    ]
   },
   {
@@ -753,14 +714,6 @@
     "L2 = []"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "3e3cec38-f8f2-4cbd-a71c-f10b13072f36",
-   "metadata": {},
-   "outputs": [],
-   "source": []
-  },
   {
    "cell_type": "code",
    "execution_count": 60,