Refactor code structure for improved readability and maintainability

.gitignore

@@ -1,3 +1,5 @@
 .venv
 
 data/
+
+.env

notebook.ipynb

@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": null,
    "id": "63f43af5",
    "metadata": {},
    "outputs": [],
@@ -921,7 +921,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 48,
+   "execution_count": null,
    "id": "2056096d",
    "metadata": {},
    "outputs": [
@@ -938,39 +938,15 @@
    ],
    "source": [
     "body_fat_chart = {\n",
-    "    \"male\": {\n",
-    "        \"20-39\": {\n",
-    "            \"bad\": [(0, 5), (25, 50)],\n",
-    "            \"okay\": [(5, 10), (20, 25)],\n",
-    "            \"good\": [(10, 20)]\n",
+    "    \"male\": { \n",
+    "        \"20-39\": { \"bad\": [(0, 5), (25, 50)], \"okay\": [(5, 10), (20, 25)], \"good\": [(10, 20)] },\n",
+    "        \"40-59\": { \"bad\": [(0, 5), (30, 50)], \"okay\": [(5, 10), (20, 30)], \"good\": [(10, 20)] },\n",
+    "        \"60-79\": { \"bad\": [(0, 5), (30, 50)], \"okay\": [(5, 10), (20, 25)], \"good\": [(10, 25)] }\n",
     "    },\n",
-    "        \"40-59\": {\n",
-    "            \"bad\": [(0, 5), (30, 50)],\n",
-    "            \"okay\": [(5, 10), (20, 30)],\n",
-    "            \"good\": [(10, 20)]\n",
-    "        },\n",
-    "        \"60-79\": {\n",
-    "            \"bad\": [(0, 5), (30, 50)],\n",
-    "            \"okay\": [(5, 10), (20, 25)],\n",
-    "            \"good\": [(10, 25)]\n",
-    "        }\n",
-    "    },\n",
-    "    \"female\": {\n",
-    "        \"20-39\": {\n",
-    "            \"bad\": [(0, 15), (40, 50)],\n",
-    "            \"okay\": [(15, 20), (35, 40)],\n",
-    "            \"good\": [(20, 35)]\n",
-    "        },\n",
-    "        \"40-59\": {\n",
-    "            \"bad\": [(0, 20), (40, 50)],\n",
-    "            \"okay\": [(20, 25), (35, 40)],\n",
-    "            \"good\": [(25, 35)]\n",
-    "        },\n",
-    "        \"60-79\": {\n",
-    "            \"bad\": [(0, 20), (40, 50)],\n",
-    "            \"okay\": [(20, 25), (35, 40)],\n",
-    "            \"good\": [(25, 35)]\n",
-    "        }\n",
+    "    \"female\": { \n",
+    "        \"20-39\": { \"bad\": [(0, 15), (40, 50)], \"okay\": [(15, 20), (35, 40)], \"good\": [(20, 35)] },\n",
+    "        \"40-59\": { \"bad\": [(0, 20), (40, 50)], \"okay\": [(20, 25), (35, 40)], \"good\": [(25, 35)] },\n",
+    "        \"60-79\": { \"bad\": [(0, 20), (40, 50)], \"okay\": [(20, 25), (35, 40)], \"good\": [(25, 35)] }\n",
     "    }\n",
     "}\n",
     "\n",