Potential bug: v_offset expected for touch_tip during transfer but cannot be set

[James-Kitson]

overview

The api reference page states:

touch_tip (boolean) – If True, a touch_tip will occur following each aspirate and dispense. If set to False (default), no touch_tip will occur.

but a warning is thrown when you follow the api instructions for performing a touch_tip.

current behavior

Running a pipette.transfer command with touch_tip=True results in a warning:

"Please use the v_offset named parameter"

steps to reproduce

from opentrons import labware, instruments

tips1000 = labware.load('opentrons-tiprack-1000ul', '1')
plate1 = labware.load('96-deep-well', '2')

pipette1000 = instruments.P1000_Single(mount='left', tip_racks=[tips1000])

pipette1000.transfer(100, plate1.well('A1'),
                     plate1.well('B1'),
                     touch_tip=True)

simulate log:

Transferring 100 from well A1 in "2" to well B1 in "2"
Picking up tip well A1 in "1"
Aspirating 100.0 uL from well A1 in "2" at 1 speed
Touching tip
Logs from this command:
WARNING (pipette): Please use the v_offset named parameter
Dispensing 100.0 uL into well B1 in "2"
Touching tip
Logs from this command:
WARNING (pipette): Please use the v_offset named parameter
Dropping tip well A1 in "12"

expected behaviour

No warning or preferably a procedure listed in the api reference for specifying the v_offset during transfer or distribute.

[James-Kitson]

This is also related to #2048 and #3599
Together they represent the ideal behaviour for a distribute touch_tip:

1. Aspirate
2. Move to first destination
3. Dispense, move to defined height and touch tip at defined height
4. Move to a new destination
5. Dispense, move to defined height and touch tip at defined height
6. ...