Balanced Abstraction Principle

Sandro Mancuso, in his blog, defines the Balanced Abstraction Principle as follows:

The Balanced Abstraction Principle defines that all code constructs grouped by a higher-level construct should be at the same level of abstraction. That means:

• All instructions inside a method should be at the same level of abstraction.
• All public methods inside a class should be at the same level of abstraction.
• All classes should be inside a package/namespace.
• All sibling packages/namespace should be inside a parent package/namespace.

Sandro Mancuso, Balanced Abstraction Principle, https://codurance.com/2015/01/27/balanced-abstraction-principle/.

Let's see how it relates to a little previous example. In the following snippet, the Save method is not at the same level of abstraction:

public class Car{
  public int CurrentMileage(){...}
  public void TravelTo(Location location){...}
  public void Save...