The "electrodes" table in NWBFile and the "bands" table in DecompositionSeries inherit from DynamicTable and add required datasets (columns) to them, but they themselves are not their own types. This makes validation problematic both at runtime and for the IO object.

Proposal: add a neurodata_type_def to these tables: Electrodes and FrequencyBands

See NeurodataWithoutBorders/pynwb#1115