docstr: Perturbation function which adds / removes punctuations
  
  Parameters
  ----------
  doc : spacy.tokens.Doc
      spacy doc
  
  Returns
  -------
  list(string)
      With punctuation removed and / or final stop added.
docstr_tok: ["Perturbation","function","which","adds","\/","removes","punctuations","Parameters","--","--","--","--","--","doc",":","spacy.tokens.Doc","spacy","doc","Returns","--","--","--","-","list","(","string",")","With","punctuation","removed","and","\/","or","final","stop","added","."]
code: def punctuation(doc):
      """Perturbation function which adds / removes punctuations
  
      Parameters
      ----------
      doc : spacy.tokens.Doc
          spacy doc
  
      Returns
      -------
      list(string)
          With punctuation removed and / or final stop added.
  
      """
      # doc is a spacy doc
      s = Perturb.strip_punctuation(doc)
      ret = []
      if s != doc.text:
          ret.append(s)
      if s + "." != doc.text:
          ret.append(s + ".")
      return ret
  
imports: import numpy
  import collections
  import re
  import os
  import json
  import pattern
  from pattern.en import tenses
  from .editor import recursive_apply, MunchWithAdd
label_desc: Use image node_id 3 for calling the Perturb obj's underlying member method code with example usage: obj.punctuation(doc) and returns: ret