get_notes_extended assistance

Looking for some assistance understanding the get_notes_extended message that can be sent to live.object.
Most of the get_notes_extended reference in the LOM makes sense to me, returns a dict, all the note data etc, but this last two paragraphs are hard to decipher.

It is possible to optionally provide the arguments to this function in the form of a single dictionary instead. The dictionary must include all of the parameter names given above as its keys; the associated values are the parameter values you wish to pass to the function.

If you use this method, you can optionally provide an additional key-value pair: the key is "return" and the associated value is a list of the note properties as listed above in the discussion of the returned note dictionaries, e.g. ["note_id", "pitch", "velocity"]. The effect of this will be that the returned note dictionaries will only contain the key-value pairs for the specified properties, which can be useful to improve patch performance when processing large notes dictionaries.

1) Is the 'function' the message "get_notes_extended" ?

2) what are the possible arguments to this message?

3) What are the definitions for these parameters?

"The dictionary must include all of the parameter names given above as its keys; the associated values are the parameter values you wish to pass to the function."
Parameters:
from_pitch [int], pitch_span [int], from_time [float], time_span [float]

4) what is the "return" key and this key-value pair?

Thanks for any help