def mergeFreqProfiles(freqp1, freqp2):
   """Returns a frequency profile from two merged frequency profiles.
      The two frequency profiles must be dictionary types.
      
      Parameters:
      
      freqp1: dictionary, i.e. frequency profile
      
      freqp2: dictionary, i.e. frequency profile
      
      This function only works with absolute frequency profiles.
      """

   return dict(((i, freqp1.get(i, 0) + freqp2.get(i, 0)) for i in set.union(set(freqp1), set(freqp2))))