Fix sample_count

Co-Authored-By: gilbertoolimpio <[email protected]>

src/skmultiflow/metrics/measure_collection.py

@@ -948,7 +948,7 @@ def add_result(self, y_true, y_pred, weight=1.0):
 
         self.total_square_error += (y_true - y_pred) * (y_true - y_pred)
         self.average_error += np.absolute(y_true - y_pred)
-        self.sample_count += weight
+        self.sample_count += 1
 
     def get_mean_square_error(self):
         """ Computes the mean square error.