There are multiple pieces of metadata and functions such as checkers and converters floating around in the datatypes module.

Currently, these are loose objects, and with recent addition of soft dependency handling I think it has passed the threshold where it would make sense to bundle these in a class.

I think the right design is:

• BaseObject descendant
• one class for: mtype checks, metadata
• one class for conversions (from/to) or pair mtype, metadata
• perhaps one class for examples - or should they be with the mtype class?