diff --git a/pkg/llms_from_scratch/utils.py b/pkg/llms_from_scratch/utils.py
index 466ca4c..174f83a 100644
--- a/pkg/llms_from_scratch/utils.py
+++ b/pkg/llms_from_scratch/utils.py
@@ -9,6 +9,8 @@ import ast
 import re
 import types
 from pathlib import Path
+import urllib.request
+import urllib.parse
 
 import nbformat
 
@@ -122,3 +124,22 @@ def import_definitions_from_notebook(nb_dir_or_path, notebook_name=None, *, extr
 
     exec(src, mod.__dict__)
     return mod
+
+def download_file(url, out_dir="."):
+    """Simple file download utility for tests."""
+    from pathlib import Path
+    out_dir = Path(out_dir)
+    out_dir.mkdir(parents=True, exist_ok=True)
+    filename = Path(urllib.parse.urlparse(url).path).name
+    dest = out_dir / filename
+    
+    if dest.exists():
+        return dest
+        
+    try:
+        with urllib.request.urlopen(url) as response:
+            with open(dest, 'wb') as f:
+                f.write(response.read())
+        return dest
+    except Exception as e:
+        raise RuntimeError(f"Failed to download {url}: {e}")