class_docstr: A constraint disallowing the modification of words within a specific
  input column.
  
  For example, can prevent modification of 'premise' during
  entailment.
class_docstr_tok: ["A","constraint","disallowing","the","modification","of","words","within","a","specific","input","column",".","For","example",",","can","prevent","modification","of","'premise","'","during","entailment","."]
docstr: Returns the word indices in current_text which are able to be
  deleted.
  
  If ``current_text.column_labels`` doesn't match
      ``self.matching_column_labels``, do nothing, and allow all words
      to be modified.
  
  If it does match, only allow words to be modified if they are not
      in columns from ``columns_to_ignore``.
docstr_tok: ["Returns","the","word","indices","in","current_text","which","are","able","to","be","deleted",".","If","``","current_text.column_labels","``","does","n't","match","``","self.matching_column_labels","``",",","do","nothing",",","and","allow","all","words","to","be","modified",".","If","it","does","match",",","only","allow","words","to","be","modified","if","they","are","not","in","columns","from","``","columns_to_ignore","``","."]
code: def _get_modifiable_indices(self, current_text):
      """Returns the word indices in current_text which are able to be
      deleted.
  
      If ``current_text.column_labels`` doesn't match
          ``self.matching_column_labels``, do nothing, and allow all words
          to be modified.
  
      If it does match, only allow words to be modified if they are not
          in columns from ``columns_to_ignore``.
      """
      if current_text.column_labels != self.matching_column_labels:
          return set(range(len(current_text.words)))
  
      idx = 0
      indices_to_modify = set()
      for column, words in zip(
          current_text.column_labels, current_text.words_per_input
      ):
          num_words = len(words)
          if column not in self.columns_to_ignore:
              indices_to_modify |= set(range(idx, idx + num_words))
          idx += num_words
      return indices_to_modify
  
imports: from textattack.constraints import PreTransformationConstraint
label_desc: Use image node_id 2 for calling the InputColumnModification obj's underlying member method code with example usage: obj._get_modifiable_indices(current_text) and returns: indices_to_modify, set