new_contents: # -*- coding: utf-8 -*-
  """
  
  Author
  ------
  Bo Zhang
  
  Email
  -----
  bozhang@nao.cas.cn
  
  Created on
  ----------
  - Wed Jan   4 14:00:00 2016
  
  Modifications
  -------------
  -
  
  Aims
  ----
  - to modify ccdproc package
  
  """
  
  import numpy as np
  import ccdproc
  from ccdproc import *
  
  __version__ = ccdproc.__version__
  
  
  class CCDData(ccdproc.CCDData):
      def rot90(self, k):
          """ Rotate self by 90 degrees in the counter-clockwise direction.
  
          Parameters
          ----------
          k : integer
              Number of times the array is rotated by 90 degrees.
  
          """
          self.data = np.rot90(self.data, k)
          return self
  
  
  def combine(*args, **kwargs):
      return CCDData(ccdproc.combine(*args, **kwargs))
  
subject: add ccdproc_mod.py: overwrite ccdproc for rot90()