Update sklearn_extra/robust/robust_weighted_estimator.py

Fix CI Python 3.8

Co-authored-by: Roman Yurchak <rth.yurchak@gmail.com>

sklearn_extra/robust/robust_weighted_estimator.py

@@ -338,7 +338,15 @@ def _get_loss_function(self, loss):
                 raise ValueError("The loss %s is not supported. " % self.loss)
 
             loss_class, args = eff_loss[0], eff_loss[1:]
-            return np.vectorize(loss_class(*args).dloss)
+			  # at the top of the file
+			  from distutils.version import LooseVersion
+
+			  if LooseVersion(sklearn.__version__) >= LooseVersion("0.24.0"):
+			      dloss_attr = 'py_dloss'
+			  else:
+			      dloss_attr = 'dloss'
+
+            return np.vectorize(geattr(loss_class(*args), dloss_attr))
         else:
             return loss