code: def make_cluster_vector(rev_dict, n_src):
      
      out_array = -1 * np.ones((n_src), int)
      for k, v in rev_dict.items():
          out_array[k] = v
          # We need this to make sure the see source points at itself
          out_array[v] = v
      return out_array
docs: Converts the cluster membership dictionary to an array
  
      Parameters
      ----------
      rev_dict : dict(int:int)    
         A single valued dictionary pointing from source index to
         cluster key for each source in a cluster. 
  
      n_src    : int
         Number of source in the array
  
      Returns
      -------
      out_array : `numpy.ndarray' 
         An array filled with the index of the seed of a cluster if a source belongs to a cluster, 
         and with -1 if it does not.