Note that you can register more than one parser for the same Type provided that you give them different variant type signatures.
If there is already a parser registered for the given
vtype it will be silently replaced.
The recommended behaviour is that Object classes register their parsers in their respective class init functions.
The Type of the object class to register a parser for
Variants to be converted must have this signature
A function to convert Variant data into an instance of the given