code: def transform(self, x):
      result = []
      for s in x:
          s = re.sub(
              r"([a-z])\1+",
              lambda m: m.group(1),
              s,
              flags=re.IGNORECASE,
          )
          s = re.sub(
              r"([a-z][a-z])\1+",
              lambda m: m.group(1),
              s,
              flags=re.IGNORECASE,
          )
          result.append(s)
      return result
  
imports: from sklearn.base import BaseEstimator, TransformerMixin
  import string
  import re
  from underthesea.pipeline.word_tokenize import tokenize
  from underthesea.utils.vietnamese_features import remove_tone
label_desc: Use image node_id 1 for calling the RemoveDuplicate obj's underlying member method code with example usage: obj.transform(x) and returns: result