Remove image for text for accessibility

Author: liamjberrisford

short_courses/figures/python_testing/type-checking.png

@@ -174,7 +174,23 @@
     "\n",
     "Copy the following code fragment into your IDE.  If type checking is enabled you should see a warning message.\n",
     "\n",
-    "![Screenshot of a Python code snippet in Visual Studio Code showing type hints and type checking errors. A dictionary word_countis annotated asdict[str, int]. Assigning a string key 'the'with integer value1is valid, but assigning an integer key2with a string value'error' triggers type errors. The editor highlights mismatched key and value types using Pylance.](figures/python_testing/type-checking.png)\n",
+    "```python\n",
+    "word_count: \"dict[str,int]\" = {}\n",
+    "\n",
+    "word_count['the'] = 1\n",
+    "word_count[2] = 'error'\n",
+    "```\n",
+    "\n",
+    "```\n",
+    "Argument of type \"Literal[2]\" cannot be assigned to parameter \"key\" of type \"str\" in function \"__setitem__\"\n",
+    "  \"Literal[2]\" is incompatible with \"str\"  Pylance(reportArgumentType)\n",
+    "\n",
+    "Argument of type \"Literal['error']\" cannot be assigned to parameter \"value\" of type \"int\" in function \"__setitem__\"\n",
+    "  \"Literal['error']\" is incompatible with \"int\"  Pylance(reportArgumentType)\n",
+    "\n",
+    "(variable) word_count: dict[str, int]\n",
+    "```\n",
+    "\n",
     "\n",
     "Without making any changes, try running the code."
    ]