message: Add methods for updating z lenth of pipette in pose tracker instead of adding on the fly
diff: @@ -13,6 +13,8 @@ class PipetteTip:
  def __init__(self, length):
  self.length = length
  +# This should come from configuration if tip length is not already in db
  +DEFAULT_TIP_LENGTH = 53.2
  class Pipette:
  """
  @@ -767,7 +769,7 @@ class Pipette:
  for i in range(int(presses) - 1):
  self.move_to(self.current_tip().top(tip_plunge), strategy='direct')
  self.move_to(self.current_tip().top(0), strategy='direct')
  -
  + self._add_tip(DEFAULT_TIP_LENGTH)
  return self
  return _pick_up_tip(self, location)
  @@ -833,7 +835,7 @@ class Pipette:
  self.current_volume = 0
  self.current_tip(None)
  -
  + self._remove_tip(DEFAULT_TIP_LENGTH)
  return self
  return _drop_tip(location)
  @@ -1380,10 +1382,13 @@ class Pipette:
  return self
  def _move(self, x=None, y=None, z=None):
  - if self.attached_tip and z is not None:
  - z += self.attached_tip.length
  -
  self.instrument_mover.move(x, y, z)
  def _probe(self, axis, movement):
  return self.instrument_mover.probe(axis, movement)
  +
  + def _add_tip(self, length):
  + self.robot.pose_tracker[self].z += length
  +
  + def _remove_tip(self, length):
  + self.robot.pose_tracker[self].z -= length
  