diff --git a/fadin/solver.py b/fadin/solver.py
index 3549384..671544b 100644
--- a/fadin/solver.py
+++ b/fadin/solver.py
@@ -3,15 +3,13 @@
 import matplotlib.pyplot as plt
 import numpy as np
 
-from fadin.utils.utils import optimizer, projected_grid, \
-    init_kernel_parameters
+from fadin.utils.utils import optimizer, projected_grid
 from fadin.utils.compute_constants import compute_constants_fadin
 from fadin.loss_and_gradient import compute_gradient_fadin
 from fadin.kernels import DiscreteKernelFiniteSupport
 from fadin.init import init_hawkes_params
 
 
-
 class FaDIn(object):
     """Define the FaDIn framework for estimated Hawkes processes.
 
diff --git a/fadin/utils/utils_simu.py b/fadin/utils/utils_simu.py
index 25dd64b..7378b7e 100644
--- a/fadin/utils/utils_simu.py
+++ b/fadin/utils/utils_simu.py
@@ -1,7 +1,7 @@
 import numpy as np
 from scipy.optimize import minimize_scalar
 from scipy.interpolate import interp1d
-from scipy.integrate import simps
+from scipy.integrate import simpson
 import scipy.stats as stats
 
 
@@ -84,7 +84,7 @@ def __init__(self, custom_density, params=dict(), kernel_length=10):
     # function to normalise the pdf over chosen domain
 
     def normalisation(self, x):
-        return simps(self.pdf(x), x)
+        return simpson(self.pdf(x), x)
 
     def create_cdf_ppf(self):
         # define normalization support with the given kernel length