Created repr for the cubic spline

tupak/gw/calibration.py

@@ -75,8 +75,14 @@ class CubicSpline(Recalibrate):
         if n_points < 4:
             raise ValueError('Cubic spline calibration requires at least 4 spline nodes.')
         self.n_points = n_points
+        self.minimum_frequency = minimum_frequency
+        self.maximum_frequency = maximum_frequency
         self.spline_points = np.logspace(np.log10(minimum_frequency), np.log10(maximum_frequency), n_points)
 
+    def __repr__(self):
+        return self.__class__.__name__ + '(prefix={}, minimum_frequency={}, maximum_frequency={}, n_points={})'\
+            .format(self.prefix, self.minimum_frequency, self.maximum_frequency, self.n_points)
+
     def get_calibration_factor(self, frequency_array, **params):
         """Apply calibration model