old_contents: 
  # external imports
  
  try:
      import numpy as np
      import numpy.linalg as la
  except:
      print 'numpy 1.3 is required'
      raise
  try:
      import scipy as sp
      import scipy.stats as stats
      from cg.kdtree import KDTree
      from scipy.spatial.distance import pdist, cdist
  except:
      print 'scipy 0.7+ is required'
      raise
  
  
  import copy
  import math
  import random
  import sys
  import time
  import unittest
  
new_contents: 
  # external imports
  
  try:
      import numpy as np
      import numpy.linalg as la
  except:
      print 'numpy 1.3 is required'
      raise
  try:
      import scipy as sp
      import scipy.stats as stats
      from cg.kdtree import KDTree
      from scipy.spatial.distance import pdist, cdist
  except:
      print 'scipy 0.7+ is required'
      raise
  
  RTOL = .0000001
  
  import copy
  import math
  import random
  import sys
  import time
  import unittest
  
subject: add common RTOL value for all to use