code: def NgramWordAnalyzer(minsize, maxsize=None, tokenizer=None, at=None):
      if not tokenizer:
          tokenizer = RegexTokenizer()
      return (
          tokenizer
          | LowercaseFilter()
          | NgramFilter(minsize, maxsize, at=at)
      )
  
file_path: whoosh/src/whoosh/analysis/ngrams.py
imports: from whoosh.compat import text_type
  from whoosh.compat import xrange
  from whoosh.analysis.acore import Token
  from whoosh.analysis.filters import Filter, LowercaseFilter
  from whoosh.analysis.tokenizers import Tokenizer, RegexTokenizer
label_desc: Use image node_id 2 for calling a global function with example usage: NgramWordAnalyzer(minsize, maxsize, tokenizer, at) and returns: unknown