Update pipeline.py

Author: glemaitre

imblearn/pipeline.py

@@ -170,6 +170,12 @@ def _validate_steps(self):
     def _iter(
         self, with_final=True, filter_passthrough=True, filter_resample=True
     ):
+        """Generate (idx, (name, trans)) tuples from self.steps
+        
+        When `filter_passthrough` is `True`, 'passthrough' and None transformers
+        are filtered out. When `filter_resample` is `True`, estimator with a
+        method `fit_resample` are filtered out.
+        """
         it = super()._iter(with_final, filter_passthrough)
         if filter_resample:
             return filter(lambda x: not hasattr(x[-1], "fit_resample"), it)