Rule 5.1.2 Avoid deep nesting of function code blocks. It should be limited to 4 levels

[kentr0w]

The nesting depth of the code block of a function is the depth of mutual inclusion between the code control blocks in the function (for example: if, for, while, when, etc.). Each level of nesting will increase the mental effort when reading code, because you need to maintain a current "stack" in your mind (for example, entering conditional statements, entering loops, etc.). Exception: The nesting levels of lambda expressions, local classes, and anonymous classes in functions are calculated based on the innermost function, and the nesting levels of enclosing methods are not accumulated. To avoid a confusion of code readers functional decomposition should be done. This will help reader to switch between context.