code: def create_index():
      analyzer = analysis.StandardAnalyzer()
      vector_format = formats.Frequency()
      schema = fields.Schema(
          path=fields.ID(stored=True),
          content=fields.TEXT(analyzer=analyzer, vector=vector_format),
          extra=fields.TEXT(stored=True),
      )
  
      ix = RamStorage().create_index(schema)
  
      w = ix.writer()
      from string import ascii_lowercase
  
      for letter, content in zip(ascii_lowercase, domain):
          w.add_document(
              path=u("/%s") % letter, content=content, extra=u("")
          )
      w.commit()
  
      return ix
  
file_path: whoosh/tests/test_classify.py
imports: from __future__ import with_statement
  from whoosh import analysis, classify, fields, formats, query, reading
  from whoosh.compat import u, text_type
  from whoosh.filedb.filestore import RamStorage
  from whoosh.util.testing import TempIndex
label_desc: Use image node_id 1 for calling a global function with example usage: create_index() and returns: ix