Add a helper base class to try map data class's attributes into
underlying dict.
TODO: this potentially duplicates data in both normal attribute
space as well as dict items space. And will require additional
standard helper logics to be overridden to ensure sync between
both space etal. Rather given distance from python internals for
a long time now, on pausing and thinking a bit, better to move
into a simpler arch where attributes are directly worked on for
dict [] style access.
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