Creates an extractor for extracting features.

The extractor acts as follows depending on the existence of certain keys within the incoming extracts:

1) Extracts contains tfma.ARROW_RECORD_BATCH_KEY

The features stored in the RecordBatch will be extracted and added to the output extract under the key tfma.FEATURES_KEY and the raw serialized inputs will be added under the tfma.INPUT_KEY. Any extracts that already exist will be merged with the values from the RecordBatch with the RecordBatch values taking precedence when duplicate keys are detected. The tfma.ARROW_RECORD_BATCH_KEY key will be removed from the output extracts.

2) Extracts contains tfma.FEATURES_KEY (but not tfma.ARROW_RECORD_BATCH_KEY)

The operation will be a no-op and the incoming extracts will be passed as is to the output.

3) Extracts contains neither tfma.FEATURES_KEY | tfma.ARROW_RECORD_BATCH_KEY

An exception will be raised.

eval_config Eval config.
tensor_representations Optional tensor representations to use when parsing the data. If tensor_representations are not passed or a representation is not found for a given feature name a default representation will be used where possible, otherwise an exception will be raised.

Extractor for extracting features.