docs: def path_niftypet_local():
      '''Get the path to the local (home) folder for NiftyPET resources.'''
      # if using conda put the resources in the folder with the environment name
      if 'CONDA_DEFAULT_ENV' in os.environ:
          env = os.environ['CONDA_DEFAULT_ENV']
          print 'i> conda environment found:', env
      else:
          env = ''
      # create the path for the resources files according to the OS platform
      if platform.system() == 'Linux' :
          path_resources = os.path.join( os.path.join(os.path.expanduser('~'),   '.niftypet'), env )
      elif platform.system() == 'Windows' :
          path_resources = os.path.join( os.path.join(os.getenv('LOCALAPPDATA'), '.niftypet'), env )
      elif platform.system() == 'Darwin':
          path_resources = os.path.join( os.path.join(os.path.expanduser('~'),   '.niftypet'), env )
      else:
          raise SystemError('e> the operating system is not recognised and therefore not supported!')
  
      return path_resources