class_docstr: Base pairwise transformer for tabular or series data template class.
  
  The base pairwise transformer specifies the methods and method signatures that all
  pairwise transformers have to implement.
  
  Specific implementations of these methods is deferred to concrete classes.
class_docstr_tok: ["Base","pairwise","transformer","for","tabular","or","series","data","template","class",".","The","base","pairwise","transformer","specifies","the","methods","and","method","signatures","that","all","pairwise","transformers","have","to","implement",".","Specific","implementations","of","these","methods","is","deferred","to","concrete","classes","."]
docstr: Fit method for interface compatibility (no logic inside).
docstr_tok: ["Fit","method","for","interface","compatibility","(","no","logic","inside",")","."]
code: def fit(self, X=None, X2=None):
      """Fit method for interface compatibility (no logic inside)."""
      # no fitting logic, but in case fit is called or expected
      self.reset()
      self._is_fitted = True
      return self
  
imports: from sktime.base import BaseEstimator
  from sktime.datatypes import check_is_scitype, convert_to
  from sktime.datatypes._series_as_panel import convert_Series_to_Panel
label_desc: Use image node_id 5 for calling the BasePairwiseTransformer obj's underlying member method code with example usage: obj.fit(X, X2) and returns: self