We used Python code to perform basic CRUD operations on our database.  It would be worthwhile to note that as applications get larger and more complex, the programmer should consider making use of an ORM (object-relational mapping) library instead of direct CRUD operations. Read more about ORM and its benefits at http://blogs.learnnowonline.com/2012/08/28/4-benefits-of-object-relational-mapping-orm/.

We used a thread lock as a synchronization primitive in 9.02_lock_demo.py. There are several other synchronization primitives that could have been used instead. Learn about other synchronization primitives at https://www.usenix.org/legacy/publications/library/proceedings/bsdcon02/full_papers/baldwin/baldwin_html/node5.html.

Python Enhancement Proposals (PEPs) are official design documents or technical specifications in the Python community that describe a new feature that has been introduced in Python. For instance, PEP 3156 is the specification dealing with and explaining the rationale behind the introduction of the asyncio module. You can read this PEP document here:
https://www.python.org/dev/peps/pep-3156/

The event loop in asyncio internally uses coroutines and futures to implement asynchronous behavior. Learning how to use coroutines and futures can be a valuable tool for writing more efficient and scalable programs.

Sockets are commonly used for interprocess communication. However, there are many other methods for interprocess communication. A brief read of http://nptel.ac.in/courses/106108101/pdf/Lecture_Notes/Mod%207_LN.pdf is well worth the effort.