old_contents: 
  from math import cos, sin
  
  
  class CameraMan(object):
  
      def __init__(self, look_at_item, amplitude, frequency=0.2):
          self.look_at_item = look_at_item
          self.amplitude = amplitude
          self.frequency = frequency
          self.center = None
          self.last_position = None
  
  
      def __call__(self, item, dt, time):
          if item.position != self.last_position:
              self.center = item.position
          offset = (
              sin(time * self.frequency) * self.amplitude[0],
              cos(time * self.frequency) * self.amplitude[1],
              0)
          self.last_position = item.position = self.center + offset
  
          if self.look_at_item.position:
              item.look_at = self.look_at_item.position
  
  
new_contents: 
  from math import cos, sin
  
  
  class CameraMan(object):
  
      def __init__(self, look_at_item, amplitude, frequency=0.2):
          self.look_at_item = look_at_item
          self.amplitude = amplitude
          self.frequency = frequency
          self.center = None
          self.last_position = (999,999,999)
  
  
      def __call__(self, item, dt, time):
          if item.position != self.last_position:
              self.center = item.position
          offset = (
              sin(time * self.frequency) * self.amplitude[0],
              cos(time * self.frequency) * self.amplitude[1],
              0)
          self.last_position = item.position = self.center + offset
  
          if self.look_at_item.position:
              item.look_at = self.look_at_item.position
  
  
subject: fix stacktrace on startup on python26