diff --git a/src/scgenerator/__init__.py b/src/scgenerator/__init__.py
index cbae4c9..b225bda 100644
--- a/src/scgenerator/__init__.py
+++ b/src/scgenerator/__init__.py
@@ -1,9 +1,10 @@
 # # flake8: noqa
 from scgenerator import math, operators, plotting
+from scgenerator.helpers import *
 from scgenerator.math import abs2, argclosest, normalized, span, tspace, wspace
 from scgenerator.parameter import FileConfiguration, Parameters
 from scgenerator.physics import fiber, materials, plasma, pulse, units
 from scgenerator.physics.units import PlotRange
-from scgenerator.utils import Paths, _open_config, open_single_config, simulations_list
-from scgenerator.solver import solve43, integrate
-
+from scgenerator.solver import integrate, solve43
+from scgenerator.utils import (Paths, _open_config, open_single_config,
+                               simulations_list)
diff --git a/src/scgenerator/helpers.py b/src/scgenerator/helpers.py
index 9d8abc4..59d0aaa 100644
--- a/src/scgenerator/helpers.py
+++ b/src/scgenerator/helpers.py
@@ -13,7 +13,6 @@ from scgenerator.math import all_zeros
 from scgenerator.parameter import Parameters
 from scgenerator.physics.fiber import beta2, n_eff_hasan, n_eff_marcatili
 from scgenerator.physics.materials import n_gas_2
-from scgenerator.physics.simulate import RK4IP
 from scgenerator.physics.units import c, nm
 
 try:
diff --git a/src/scgenerator/physics/units.py b/src/scgenerator/physics/units.py
index b1ebd02..28aec79 100644
--- a/src/scgenerator/physics/units.py
+++ b/src/scgenerator/physics/units.py
@@ -10,6 +10,7 @@ from typing import Callable, TypeVar, Union
 import numpy as np
 from numpy import pi
 
+
 c = 299792458.0
 hbar = 1.05457148e-34
 NA = 6.02214076e23