Differences between __post_pcell_init__ & __post_init__

Both methods are commonly used in PhotoCAD to perform data validation on the class after initializing it. For example, in gpdk >> examples >> examples_cosine_bend.py, we use __post_init__ method to check if the parameters are well-set when we initialize the class.

Another example of __post_pcell_init__ is in gpdk >> components >> bend >> bend_circular.py when we want to check if the degree of the circular bend is a non-zero value.

The major difference between the two initializations is the time that runs the action. __post_init__ runs directly after the class was generated (to be more specific, after setting the parameters of the PCell) but before the _default_factory was created. On the other hand, __post_pcell_init__ will run after setting the parameters of the PCell and the _default_factory. It allows users more convenience to set the values of the components by _default_factory function and check those afterward.