diff --git a/README.md b/README.md
index 242b349..047c443 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
+
+
+
 # Learn Python Programming 3rd Edition
 
 Welcome to Learn Python Programming, 3rd Edition.
@@ -29,6 +32,16 @@ that might suit you better.
 We have given the virtual environment folder the name `.venv`. Feel free
 to choose any other name that you might want.
 
+---
+
+Note: the above procedure might fail in some of the chapter folders, due
+to the presence of files that aren't meant to be run. If that is the case, you
+should choose another folder where to place your virtual environment. You can
+create one within the chapter folder itself, or place the virtual environment
+outside of the chapter folder altogether.
+
+---
+
 Next step is to activate the virtual environment:
 
     $ source  .venv/bin/activate
@@ -52,3 +65,7 @@ find all the instructions you need in the chapter's text.
 **Note**:
 Always remember to activate the virtual environment before you install
 third-party libraries.
+### Download a free PDF
+
+ <i>If you have already purchased a print or Kindle version of this book, you can get a DRM-free PDF version at no cost.<br>Simply click on the link to claim your free PDF.</i>
+<p align="center"> <a href="https://packt.link/free-ebook/9781801815093">https://packt.link/free-ebook/9781801815093 </a> </p>
\ No newline at end of file
diff --git a/ch08/files/compression/tar.py b/ch08/files/compression/tar.py
index 69af6c2..593c0fc 100644
--- a/ch08/files/compression/tar.py
+++ b/ch08/files/compression/tar.py
@@ -8,4 +8,26 @@
     tar.add('subfolder/content4.txt')
 
 with tarfile.open('example.tar.gz', 'r:gz') as tar:
-    tar.extractall('extract_tar')
+    
+    import os
+    
+    def is_within_directory(directory, target):
+        
+        abs_directory = os.path.abspath(directory)
+        abs_target = os.path.abspath(target)
+    
+        prefix = os.path.commonprefix([abs_directory, abs_target])
+        
+        return prefix == abs_directory
+    
+    def safe_extract(tar, path=".", members=None, *, numeric_owner=False):
+    
+        for member in tar.getmembers():
+            member_path = os.path.join(path, member.name)
+            if not is_within_directory(path, member_path):
+                raise Exception("Attempted Path Traversal in Tar File")
+    
+        tar.extractall(path, members, numeric_owner=numeric_owner) 
+        
+    
+    safe_extract(tar, "extract_tar")