class_docstr: Only indexes whether a given term occurred in a given document; it does
  not store frequencies or positions. This is useful for fields that should
  be searchable but not scorable, such as file path.
  
  Supports: frequency, weight (always reports frequency = 1).
class_docstr_tok: ["Only","indexes","whether","a","given","term","occurred","in","a","given","document",";","it","does","not","store","frequencies","or","positions",".","This","is","useful","for","fields","that","should","be","searchable","but","not","scorable",",","such","as","file","path",".","Supports",":","frequency",",","weight","(","always","reports","frequency","=","1",")","."]
code: def decode_weight(self, valuestring):
      return self.field_boost
  
imports: from collections import defaultdict
  from whoosh.analysis import unstopped, entoken
  from whoosh.compat import iteritems, dumps, loads, b
  from whoosh.system import emptybytes
  from whoosh.system import _INT_SIZE, _FLOAT_SIZE
  from whoosh.system import pack_uint, unpack_uint, pack_float, unpack_float
label_desc: Use image node_id 5 for calling the Existence obj's underlying member method code with example usage: obj.decode_weight(valuestring) and returns: self