class_docstr: Text span index class.
  Holds TF and DF values per span. Text spans are normalized and similar
  spans are mapped to the same TF DF values.
class_docstr_tok: ["Text","span","index","class",".","Holds","TF","and","DF","values","per","span",".","Text","spans","are","normalized","and","similar","spans","are","mapped","to","the","same","TF","DF","values","."]
code: def get_phrase(self, pid):
      return self.pid_to_spans.get(pid)
  
imports: import itertools
  import math
  import numpy
  import logging
  from spacy.tokens.doc import Doc
  from spacy.tokens.span import Span
  from spacy.tokens.token import Token
label_desc: Use image node_id 2 for calling the CorpusIndex obj's underlying member method code with example usage: obj.get_phrase(pid) and returns: self