def node_def_remove_inputs(sss):
  """ remove inputs in a node_def.

  Args:
    sss: original node_def of an op.

  Returns:
    new string of node_def.
  """
  idx = sss.find('input: "')
  while idx > 0:
    idx_e = sss.find('"', idx + 9)
    tmpstr = sss[idx:(idx_e+1)]
    sss = sss.replace(tmpstr, '')
    idx = sss.find('input: "')
  return sss