code: def write_sparse_npz(E, filename, compressed = False):
      ''' SPRING standard: filename = main_spring_dir + "/counts_norm.npz"'''
      E = E.tocsc()
      scipy.sparse.save_npz(filename, E, compressed = compressedf write_sparse_npz(E, filename, compressed = False):
      ''' SPRING standard: filename = main_spring_dir + "/counts_norm.npz"'''
      E = E.tocsc()
      scipy.sparse.save_npz(filename, E, compressed = compressed)
docs: SPRING standard: filename = main_spring_dir + "/counts_norm.npz"