diff --git a/experiment/trend_analysis/univariate_test/abstract_trend_test.py b/experiment/trend_analysis/univariate_test/abstract_trend_test.py
index 195d685f8b6c43b236cda26200e70bb079d1784a..9304b779d4a9641cef1c7933c7489bc43f2cef63 100644
--- a/experiment/trend_analysis/univariate_test/abstract_trend_test.py
+++ b/experiment/trend_analysis/univariate_test/abstract_trend_test.py
@@ -1,13 +1,8 @@
-import random
 import warnings
 
-import matplotlib.pyplot as plt
-from collections import OrderedDict
-
 import numpy as np
-from cached_property import cached_property
 
-from experiment.trend_analysis.mann_kendall_test import mann_kendall_test
+from experiment.trend_analysis.univariate_test.mann_kendall_test import mann_kendall_test
 from experiment.trend_analysis.abstract_score import MannKendall
 from experiment.trend_analysis.univariate_test.abstract_univariate_test import AbstractUnivariateTest
 
diff --git a/experiment/trend_analysis/univariate_test/abstract_univariate_test.py b/experiment/trend_analysis/univariate_test/abstract_univariate_test.py
index 1376addeac92f0f693e24ed172f74e1227908c49..a039b9d97ad619e30cdef0acde7cd906fbc68c5f 100644
--- a/experiment/trend_analysis/univariate_test/abstract_univariate_test.py
+++ b/experiment/trend_analysis/univariate_test/abstract_univariate_test.py
@@ -1,16 +1,10 @@
 import random
-import warnings
-
-import matplotlib.pyplot as plt
 from collections import OrderedDict
 
-import numpy as np
+import matplotlib.pyplot as plt
 from cached_property import cached_property
 from matplotlib import colors
 
-from experiment.trend_analysis.mann_kendall_test import mann_kendall_test
-from experiment.trend_analysis.abstract_score import MannKendall
-
 
 class AbstractUnivariateTest(object):
     SIGNIFICATIVE = 'significative'
diff --git a/experiment/trend_analysis/mann_kendall_test.py b/experiment/trend_analysis/univariate_test/mann_kendall_test.py
similarity index 100%
rename from experiment/trend_analysis/mann_kendall_test.py
rename to experiment/trend_analysis/univariate_test/mann_kendall_test.py
diff --git a/extreme_estimator/estimator/abstract_estimator.py b/extreme_estimator/estimator/abstract_estimator.py
index 857fef72b9d33d0f060412f036aba0f80a6ff04f..73f453ea69163df41f06ce3f0e73c3e8c98dce1a 100644
--- a/extreme_estimator/estimator/abstract_estimator.py
+++ b/extreme_estimator/estimator/abstract_estimator.py
@@ -58,11 +58,6 @@ class AbstractEstimator(object):
                                                    coef_dict=self.result_from_fit.margin_coef_dict,
                                                    starting_point=margin_model.starting_point)
 
-    # @property
-    # def max_stable_fitted(self) -> AbstractMarginFunction:
-    #     assert self._margin_function_fitted is not None, 'Error: estimator has not been fitted'
-    #     return self._margin_function_fitted
-
     @property
     def train_split(self):
         return self.dataset.train_split
diff --git a/extreme_estimator/estimator/margin_estimator/abstract_margin_estimator.py b/extreme_estimator/estimator/margin_estimator/abstract_margin_estimator.py
index 8a747fde45f0cbab5501c296d6761140fa4ab68e..220d4b5703ed0d2762536e39a352dd8e0ec214ea 100644
--- a/extreme_estimator/estimator/margin_estimator/abstract_margin_estimator.py
+++ b/extreme_estimator/estimator/margin_estimator/abstract_margin_estimator.py
@@ -39,7 +39,9 @@ class LinearMarginEstimator(AbstractMarginEstimator):
 
     @property
     def margin_function_fitted(self) -> LinearMarginFunction:
-        return super().margin_function_fitted
+        margin_function_fitted = super().margin_function_fitted
+        assert isinstance(margin_function_fitted, LinearMarginFunction)
+        return margin_function_fitted
 
     def extract_function_fitted(self) -> LinearMarginFunction:
         return self.extract_function_fitted_from_the_model_shape(self.margin_model)