midict (pypi): MIDict (Multi-Index Dict) can be indexed by any "keys" or "values", suitable as a bidirectional/inverse dict or a multi-key/multi-value dict (a drop-in replacement for dict in Python 2 & 3).
Keywords: dict|dictionary|mapping|bidirectional|bijective|two-way|double|inverse|reverse|multiple|index|multiple indices|multiple values|multiple keys|MIMapping|MIDict|FrozenMIDict|AttrDict|IndexDict|multi-indexing syntax|frozen-dict|multi-indexing|multi-key|multi-value