class_docstr: Filter samples based on text length
  
  Example::
  
      sample 1: "I love textflint", score: 3
      sample 2: "I love textflint very much", score: 5
class_docstr_tok: ["Filter","samples","based","on","text","length","Example",":",":","sample","1",":","``","I","love","textflint","''",",","score",":","3","sample","2",":","``","I","love","textflint","very","much","''",",","score",":","5"]
docstr: Calculate the score based on text length
  
  :param sample: data sample
  :param list fields: list of field str
  :param kwargs:
  :return int: score for sample
docstr_tok: ["Calculate","the","score","based","on","text","length",":","param","sample",":","data","sample",":","param","list","fields",":","list","of","field","str",":","param","kwargs",":",":","return","int",":","score","for","sample"]
code: def _score(self, sample, fields, **kwargs):
      r"""
      Calculate the score based on text length
  
      :param sample: data sample
      :param list fields: list of field str
      :param kwargs:
      :return int: score for sample
  
      """
      words = []
      for field in fields:
          words += sample.get_words(field)
      return len(words)
  
imports: from ..subpopulation import SubPopulation
label_desc: Use image node_id 3 for calling the LengthSubPopulation obj's underlying member method code with example usage: obj._score(sample, fields) and returns: len