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README.md

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+# Learn Python Programming 3rd Edition
+
+Welcome to Learn Python Programming, 3rd Edition.
+
+Here you can find the complete source code for this book. Every
+line of code you will find in the book is in this repository, plus
+all the code that we couldn't fit in the book.
+
+## Working on a chapter
+
+We suggest you create a dedicated virtual environment for each chapter
+you wish to work on. Chapters that require third-party libraries will
+have a folder inside, called `requirements`.
+
+First you will need to create a virtual environment. If you don't know
+what a virtual environment is, please read Chapter 1.
+
+Let's now pretend you want to work on Chapter 12. First, change into the folder
+for Chapter 12 (it's called `ch12`):
+
+    $ cd ch12
+
+Then, create a virtual environment. In this example the virtual environment
+will live inside the chapter's folder, but you can choose any other folder
+that might suit you better.
+
+    $ python3.9 -m venv .venv
+
+We have given the virtual environment folder the name `.venv`. Feel free
+to choose any other name that you might want.
+
+Next step is to activate the virtual environment:
+
+    $ source  .venv/bin/activate
+
+If you're on Windows, to activate your environment, you will need to run:
+
+    $ .venv\Scripts\activate
+
+Next, if the `requirements` folder is present, change into it, and run
+the following command for each of the `.txt` files you will find in it.
+Normally there is only a `requirements.txt` file.
+
+    $ cd requirements
+    $ pip install -U -r requirements.txt
+    $ cd ..  # this brings you back to the root of the chapter
+
+Once you have installed all requirements, you are ready to run the
+chapter's code. If a chapter needs extra work to be set up, you will
+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.