class_docstr: ```
  Node preprocessing base class
  ```
class_docstr_tok: ["``","`","Node","preprocessing","base","class","``","`"]
docstr: ```
  check validity of node IDs
  ```
docstr_tok: ["``","`","check","validity","of","node","IDs","``","`"]
code: def ids_exist(self, node_ids):
      """
      ```
      check validity of node IDs
      ```
      """
      df = self.df[self.df.index.isin(node_ids)]
      return df.shape[0] > 0
  
imports: from ..None import utils
  from ..imports import *
  from ..preprocessor import Preprocessor
label_desc: Use image node_id 6 for calling the NodePreprocessor obj's underlying member method code with example usage: obj.ids_exist(node_ids) and returns: unknown