message: sets pick up tip distance to top of file; uses driver.default_speed
diff: @@ -20,6 +20,8 @@ PLUNGER_POSITIONS = {
  DEFAULT_ASPIRATE_SPEED = 20
  DEFAULT_DISPENSE_SPEED = 40
  +DEFAULT_TIP_PRESS_MM = -10
  +
  class PipetteTip:
  def __init__(self, length):
  @@ -352,7 +354,7 @@ class Pipette:
  self.robot.poses,
  x=mm_position
  )
  - self.instrument_actuator.set_speed('default')
  + self.instrument_actuator.default_speed()
  self.current_volume += volume # update after actual aspirate
  return self
  @@ -438,7 +440,7 @@ class Pipette:
  self.robot.poses,
  x=mm_position
  )
  - self.instrument_actuator.set_speed('default')
  + self.instrument_actuator.default_speed()
  self.current_volume -= volume # update after actual dispense
  return self
  @@ -832,7 +834,10 @@ class Pipette:
  return self
  return _pick_up_tip(
  - self, location=location, presses=presses, plunge_depth=-10)
  + self,
  + location=location,
  + presses=presses,
  + plunge_depth=DEFAULT_TIP_PRESS_MM)
  def drop_tip(self, location=None, home_after=True):
  """
  