class_docstr: An abstract class that represents constraints on adversial text
  examples. Constraints evaluate whether transformations from a
  ``AttackedText`` to another ``AttackedText`` meet certain conditions.
  
  Args:
      compare_against_original (bool): If `True`, the reference text should be the original text under attack.
          If `False`, the reference text is the most recent text from which the transformed text was generated.
          All constraints must have this attribute.
class_docstr_tok: ["An","abstract","class","that","represents","constraints","on","adversial","text","examples",".","Constraints","evaluate","whether","transformations","from","a","``","AttackedText","``","to","another","``","AttackedText","``","meet","certain","conditions",".","Args",":","compare_against_original","(","bool",")",":","If","`","True","`",",","the","reference","text","should","be","the","original","text","under","attack",".","If","`","False","`",",","the","reference","text","is","the","most","recent","text","from","which","the","transformed","text","was","generated",".","All","constraints","must","have","this","attribute","."]
docstr: Returns True if the constraint is fulfilled, False otherwise. Must
  be overridden by the specific constraint.
  
  Args:
      transformed_text: The candidate transformed ``AttackedText``.
      reference_text (AttackedText): The ``AttackedText`` to compare against.
docstr_tok: ["Returns","True","if","the","constraint","is","fulfilled",",","False","otherwise",".","Must","be","overridden","by","the","specific","constraint",".","Args",":","transformed_text",":","The","candidate","transformed","``","AttackedText","``",".","reference_text","(","AttackedText",")",":","The","``","AttackedText","``","to","compare","against","."]
code: def _check_constraint(self, transformed_text, reference_text):
      """Returns True if the constraint is fulfilled, False otherwise. Must
      be overridden by the specific constraint.
  
      Args:
          transformed_text: The candidate transformed ``AttackedText``.
          reference_text (AttackedText): The ``AttackedText`` to compare against.
      """
      raise NotImplementedError()
  
file_path: TextAttack/textattack/constraints/constraint.py
imports: from abc import ABC, abstractmethod
  import textattack
  from textattack.shared.utils import ReprMixin
label_desc: Use image node_id 5 for calling the Constraint obj's underlying member method code with example usage: obj._check_constraint(transformed_text, reference_text) without return types