Returns a map from key to an ordered list of artifacts for the given execution id.

The dict is constructed purely from information stored in MLMD for the execution given by execution_id. The "key" is the tag associated with the InputSpec or OutputSpec in the pipeline IR.

metadata_handler A handler to access MLMD.
execution_id Id of the execution for which to get artifacts.
event_type Event type to filter by.

A dict mapping key to an ordered list of artifacts.

ValueError If the events are badly formed and correct ordering of artifacts cannot be determined or if all the artifacts could not be fetched from MLMD.