class_docstr: An identity filter: passes the tokens through untouched.
      
class_docstr_tok: ["An","identity","filter",":","passes","the","tokens","through","untouched","."]
code: def __call__(self, tokens):
      return tokens
  
imports: from itertools import chain
  from whoosh.compat import next
  from whoosh.analysis.acore import Composable
  from whoosh.util.text import rcompile
label_desc: Use image node_id 1 for calling the PassFilter obj's underlying member method code with example usage: obj.__call__(tokens) and returns: tokens