diff --git a/sem/conditionalrunner.py b/sem/conditionalrunner.py
index acfbe5f..fb2831b 100644
--- a/sem/conditionalrunner.py
+++ b/sem/conditionalrunner.py
@@ -2,9 +2,6 @@
 from multiprocessing import Pool, Queue, Lock, Array, cpu_count
 import queue
 import copy
-import numpy as np
-from copy import deepcopy
-import itertools
 from tqdm import tqdm
 
 
diff --git a/sem/lptrunner.py b/sem/lptrunner.py
index c15b2e2..dbf4b73 100644
--- a/sem/lptrunner.py
+++ b/sem/lptrunner.py
@@ -1,9 +1,8 @@
 from .runner import SimulationRunner
-from multiprocessing import Pool, Queue, Lock, Array, cpu_count
+from multiprocessing import Pool, Queue, Lock, Array
 import queue
 import numpy as np
 from copy import deepcopy
-import itertools
 
 
 def have_same_combination(dict1, dict2):
diff --git a/sem/manager.py b/sem/manager.py
index d685972..d4fb806 100644
--- a/sem/manager.py
+++ b/sem/manager.py
@@ -1,5 +1,4 @@
 import collections
-import gc
 import os
 import shutil
 from copy import deepcopy
@@ -16,9 +15,7 @@
 
 from .database import DatabaseManager
 from .lptrunner import LptRunner
-from .parallelrunner import ParallelRunner
 from .conditionalrunner import ConditionalRunner
-from .runner import SimulationRunner
 from .utils import DRMAA_AVAILABLE, list_param_combinations
 import pandas as pd
 
diff --git a/sem/runner.py b/sem/runner.py
index ac9df28..2970ffe 100644
--- a/sem/runner.py
+++ b/sem/runner.py
@@ -6,7 +6,6 @@
 import uuid
 import sem.utils
 import sys
-from importlib.machinery import SourceFileLoader
 import types
 from .utils import CallbackBase
 
diff --git a/sem/utils.py b/sem/utils.py
index 5b5c50c..fbdce6f 100644
--- a/sem/utils.py
+++ b/sem/utils.py
@@ -2,14 +2,11 @@
 import math
 import copy
 import warnings
-from itertools import product
 from functools import wraps
 from abc import ABC, abstractmethod
-from typing import Dict, Any
 
-import matplotlib.pyplot as plt
 import numpy as np
-import numpy.core.numeric as nx
+import numpy._core.numeric as nx
 import SALib.analyze.sobol
 import SALib.sample.saltelli