The mapping type was left out intentionally, with the thought that Python already has a few mapping types built-in, most notably `dict`. There is an argument to be made for adding it, as FindInMap is supported by cfn-pyplates, but that sword cuts both ways; I would equally consider removing find_in_map from `cfn_pyplates.functions`.

My assumption was/is that the Mappings object is only used self-referentially within a template, and that supporting it doesn't add functionality that isn't already provided by Python itself. Am I missing something in that assumption?