diff --git a/pyFTS/common/transformations/trend.py b/pyFTS/common/transformations/trend.py
index df67a46..6384f68 100644
--- a/pyFTS/common/transformations/trend.py
+++ b/pyFTS/common/transformations/trend.py
@@ -1,4 +1,8 @@
 from pyFTS.common.transformations.transformation import Transformation 
+from pandas import datetime
+from sklearn.linear_model import LinearRegression
+import numpy as np
+import pandas as pd
 
 
 class LinearTrend(Transformation):
@@ -24,8 +28,6 @@ class LinearTrend(Transformation):
         '''Regression model'''
 
     def train(self, data, **kwargs):
-        from pandas import datetime
-        from sklearn.linear_model import LinearRegression
 
         x = data[self.index_field].values
 
@@ -79,4 +81,4 @@ class LinearTrend(Transformation):
             ret = pd.Series(ret)
             ret = pd.to_numeric(ret, downcast='integer')
 
-        return np.array(ret)
\ No newline at end of file
+        return np.array(ret)