What's the difference between supported properties and Stored properties?

[superstar54]

In the user guide, one print out the properties:

The whole list of currently supported properties is: 
['symbols', 'cell', 'mass', 'charge', 'positions', 'pbc', 'custom', 'kinds']
Stored properties are: 
['symbols', 'cell', 'mass', 'positions', 'pbc', 'kinds']

Why charge and custom is not stored?

[mikibonacci]

Hi @superstar54, the stored properties are the one that you define. The supported properties are the one that you can define. The custom is for now just a placeholder, not yet implemented.

If you do not define charges in the input dictionary for the structuredata constructor, it will not stored