code: def pan(self):
      if isinstance(self._pan, Variable):
          return np.array(self._pan.value, dtype=np.float32)
      else:
          raise NotImplementedError()
  
imports: import numpy
  import math
  from vispy import gloo, app, scene
  from vispy.visuals import Visual
  from vispy.visuals.shaders import Function, Variable
  from vispy.visuals.transforms import TransformSystem, BaseTransform
  from vispy.util.profiler import Profiler
label_desc: Use image node_id 2 for calling the PanZoomTransform obj's underlying member method code with example usage: obj.pan() and returns: np