diff --git a/lectures/lecture4/lab/lab-4.md b/lectures/lecture4/lab/lab-4.md
index 32bb7f8e6c1941a9061ca03538f4ee735e540610..2f02e20ffa23c1dec66e182e0d7a3e3c1a1ba4a3 100644
--- a/lectures/lecture4/lab/lab-4.md
+++ b/lectures/lecture4/lab/lab-4.md
@@ -5,9 +5,11 @@
 * Lære i lage lister, kopiere og redigere
 * Forstå forskjellen mellom lister og tupler
 * Bruke løkker for å traversere lister
+* Jobbe med sets
 
 ## Læringsaktiviteter
 
 * [Generelt om lister](generelt_om_lister.ipynb)
 * [Lister og løkker](lister_og_lokker.ipynb)
 * [Tupler](lister_og_tupler.ipynb)
+* [Sets](generelt_om_sets.ipynb)
diff --git a/lectures/lecture5/lab/generelt_om_filbehandling.ipynb b/lectures/lecture5/lab/generelt_om_filbehandling.ipynb
index 7448c2d3b1f29c82df10c7e39f393c355e88ab38..0a1666082ce21c2fd9963fd84463b2fed9fc3c52 100644
--- a/lectures/lecture5/lab/generelt_om_filbehandling.ipynb
+++ b/lectures/lecture5/lab/generelt_om_filbehandling.ipynb
@@ -1,6 +1,7 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {
     "run_control": {
@@ -8,29 +9,6 @@
     }
    },
    "source": [
-    "<nav class=\"navbar navbar-default\">\n",
-    "  <div class=\"container-fluid\">\n",
-    "    <div class=\"navbar-header\">\n",
-    "      <a class=\"navbar-brand\" href=\"_Oving7.ipynb\">Øving 7</a>\n",
-    "    </div>\n",
-    "    <ul class=\"nav navbar-nav\">\n",
-    "    <li><a href=\"Generelt%20om%20dictionary.ipynb\">Generelt om dictionary</a></li>\n",
-    "    <li><a href=\"Innebygde%20funksjoner%20i%20dictionaries.ipynb\">Innebygde funksjoner</a></li>\n",
-    "    <li><a href=\"Generelt%20om%20sets.ipynb\">Generelt om sets</a></li>\n",
-    "    <li class = \"active\"><a href=\"Generelt%20om%20filbehandling.ipynb\">Generelt om filbehandling</a></li>\n",
-    "    <li><a href=\"Osteviruset.ipynb\">Osteviruset</a></li>\n",
-    "    <li><a href=\"Bursdagsdatabasen.ipynb\">Bursdagsdatabasen</a></li>\n",
-    "    <li><a href=\"Tallak%20teller%20antall%20tall.ipynb\">Tallak teller antall tall</a></li>\n",
-    "    <li><a href=\"Enhetstesting.ipynb\">Enhetstesting</a></li>\n",
-    "    <li><a href=\"Tidtaking.ipynb\">Tidtaking</a></li>\n",
-    "    <li><a href=\"Moduler.ipynb\">Moduler</a></li>\n",
-    "    <li><a href=\"Opptaksgrenser.ipynb\">Opptaksgrenser</a></li>\n",
-    "    <li><a href=\"Soke%20i%20tekst.ipynb\">Søke i tekst</a></li>\n",
-    "    <li><a href=\"Tre%20paa%20rad.ipynb\">Tre på rad</a></li>\n",
-    "    </ul>\n",
-    "  </div>\n",
-    "</nav>\n",
-    "\n",
     "# Generelt om filbehandling\n",
     "\n",
     "**Læringsmål:**\n",
diff --git a/lectures/lecture5/notes/slides/lecture-5.md b/lectures/lecture5/notes/slides/lecture-5.md
index e3de2040f283ea214eae70d01c5d5747a184a3fa..9ce55e5ea8c6c1dc31e0811ef120d51bbe21ef33 100644
--- a/lectures/lecture5/notes/slides/lecture-5.md
+++ b/lectures/lecture5/notes/slides/lecture-5.md
@@ -9,7 +9,7 @@ paginate: true
 
 **Læringsutbytte**
 
-* 
+* Lære å lese fra og skrive til fil
 
 ---
 
diff --git a/lectures/lectures.ipynb b/lectures/lectures.ipynb
index 5ab3e8dd15bccd725bbbc1664eec223ec63b19ae..204e00a75da12aff97e8bf166a6f4a64cf0929b0 100644
--- a/lectures/lectures.ipynb
+++ b/lectures/lectures.ipynb
@@ -2,134 +2,9 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": null,
    "metadata": {},
-   "outputs": [
-    {
-     "data": {
-      "text/markdown": [
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">LBAS2002 Informatikk: Programmering</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;<a target=\"_blank\" href=https://www.ntnu.no/studier/emner/LBAS2002>Faginnhold og læringsutbytte beskrivelser</a></blockquote>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">Leksjoner</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 1: Introduksjon, Variabler og Datatyper</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Introduksjon</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Motivasjon (slides)</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/notes/slides/introduksjon.pdf>Introduksjon</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Kilder og referanser</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/README.md>Readme</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Utviklingsmiljø</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/notes/codes/intro_til_jupyter.ipynb>Komme i gang med Jupyter Notebook</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Variabler og datatyper</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Variabler</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/notes/codes/variabler.ipynb>Enkle datatyper</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Datatyper</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/notes/codes/tall_og_typekonvertering.ipynb>Tall og type konvertering</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 1</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture1/lab/lab-1.md>Lab-1</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 2: Funksjoner og pakker, logiske uttrykk, valg</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Introduksjon (slides)</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/slides/lecture-2.pdf>Introduksjon</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Funksjoner</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/funksjoner_og_kalkulasjoner.ipynb>Funksjoner og kalkulasjoner</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Pakker</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/pakker.ipynb>Pakker og moduler</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Logiske uttrykk</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/logiske_operatorer_uttrykk.ipynb>Logiske operasjoner</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Ulike typer if-setninger</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/ulike_typer_if_setninger.ipynb>Ulike typr if-setninger</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 2</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/lab/lab-2.md>Lab-2</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 3: Mer om valg, løkker</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Valg</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/ulike_typer_if_setninger.ipynb>if-setninger</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Sammenligning</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture2/notes/codes/sammenligning_av_strenger.ipynb>Sammenligning av strenger</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Løkker</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Introduksjon til løkker</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;lecture3/notes/codes/intro_til_lokker.ipynb</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Mer om løkker</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;lecture3/notes/codes/mer_om_lokker.ipynb</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Nøstede løkker</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;lecture3/notes/codes/nostede_lokker.ipynb</blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 3</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture3/lab/lab-3.md>Lab-3</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 4: Sammensatte datatyper (lister, tupler, set)</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Sammensatte datatyper</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Lister</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture4/notes/codes/generelt_om_lister.ipynb>Generelt om lister</a></blockquote>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture4/notes/codes/lister_og_lokker.ipynb>Lister og løkker</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Tupler</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture4/notes/codes/lister_og_tupler.ipynb>Generelt om tupler</a></blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Set</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture4/notes/codes/lister_og_set.ipynb>Generelt om set</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 4</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture4/lab/lab-4.md>Lab-4</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 5: Filbehandling, unntakshåndtering</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Filbehandling</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Lesing fra fil</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;&emsp;Skriving til fil</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;&emsp;</blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Unntakshåndtering</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Programmering mot databaser</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 5</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture5/lab/lab-5.md>Lab-5</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;Leksjon 6: Introduksjon til objekt orientert programmering</summary>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Object Orientert Programmering</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;Introduksjon</blockquote>\n",
-       "</details>\n",
-       "<details><summary style=\"font-size:200%;cursor: pointer;\">&emsp;&emsp;Lab 6</summary>\n",
-       "<blockquote style=\"font-size:200%;cursor: pointer;padding: 10px;\">&emsp;&emsp;&emsp;<a target=\"_blank\" href=lecture6/lab/lab-6.md>Lab-6</a></blockquote>\n",
-       "</details>\n",
-       "</details>\n"
-      ],
-      "text/plain": [
-       "<IPython.core.display.Markdown object>"
-      ]
-     },
-     "metadata": {},
-     "output_type": "display_data"
-    }
-   ],
+   "outputs": [],
    "source": [
     "from IPython.display import Markdown, display\n",
     "%run lectures.py lectures.json lectures.md\n",
diff --git a/lectures/lectures.md b/lectures/lectures.md
index 52b82d1d4ab35f924b7841b5cf674925a677f464..9094a0bd8b27091817427effb255cb12f4883ff9 100644
--- a/lectures/lectures.md
+++ b/lectures/lectures.md
@@ -71,6 +71,9 @@
 </details>
 </details>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;Leksjon 4: Sammensatte datatyper (lister, tupler, set)</summary>
+<details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;Introduksjon (slides)</summary>
+<blockquote style="font-size:200%;cursor: pointer;padding: 10px;">&emsp;&emsp;&emsp;<a target="_blank" href=lecture4/notes/slides/lecture-4.pdf>Introduksjon</a></blockquote>
+</details>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;Sammensatte datatyper</summary>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;&emsp;Lister</summary>
 <blockquote style="font-size:200%;cursor: pointer;padding: 10px;">&emsp;&emsp;&emsp;&emsp;<a target="_blank" href=lecture4/notes/codes/generelt_om_lister.ipynb>Generelt om lister</a></blockquote>
@@ -88,6 +91,9 @@
 </details>
 </details>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;Leksjon 5: Filbehandling, unntakshåndtering</summary>
+<details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;Introduksjon (slides)</summary>
+<blockquote style="font-size:200%;cursor: pointer;padding: 10px;">&emsp;&emsp;&emsp;<a target="_blank" href=lecture5/notes/slides/lecture-5.pdf>Introduksjon</a></blockquote>
+</details>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;Filbehandling</summary>
 <details><summary style="font-size:200%;cursor: pointer;">&emsp;&emsp;&emsp;Lesing fra fil</summary>
 <blockquote style="font-size:200%;cursor: pointer;padding: 10px;">&emsp;&emsp;&emsp;&emsp;</blockquote>