diff --git a/src/matrix.py b/src/matrix.py
index c0f8acd..afcc479 100644
--- a/src/matrix.py
+++ b/src/matrix.py
@@ -1,7 +1,6 @@
 import math
 
 import numpy
-from numpy import linalg
 
 
 class Matrix:
@@ -76,9 +75,8 @@ class Matrix:
                 self.__shape__ = (len(data), len(data[0]))
             self.__data__ = data
         else:
-            raise ValueError(
-                "Only following signatures are allowed: "
-                "(list), (numpy.ndarray), (list, tuple), (list, str, int), (list, str, int, int), (str, int)")
+            raise ValueError("Only following signatures are allowed: "
+                             "(list), (numpy.ndarray), (list, tuple), (list, str, int), (list, str, int, int), (str, int)")
 
     def get_data(self):
         """
@@ -243,7 +241,7 @@ class Matrix:
             abs_sum = 0
             for i in range(rows):
                 for j in range(cols):
-                    abs_sum += abs(self.__data__[i][j])**2
+                    abs_sum += abs(self.__data__[i][j]) ** 2
             norm = math.sqrt(abs_sum)
         elif f == "col sum":
             row_sum = [0 for _ in range(cols)]
diff --git a/test/test_serial.py b/test/test_serial.py
index 8d7d5bd..645ddf9 100644
--- a/test/test_serial.py
+++ b/test/test_serial.py
@@ -34,9 +34,9 @@ print(f"vec_x2.T() has shape {vec_x2.T().shape()} | must be (1,10000)")
 print(f"vec_x2.T().T() has shape {vec_x2.T().T().shape()} | must be (10000,1)")
 print("End 1c\n")
 
-### 1d addition and substraction
-print("Start 1d addition and substraction")
-# intitialization
+### 1d addition and subtraction
+print("Start 1d addition and subtraction")
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 b = Vector([-2, 5, 1, 0, -3])
 # computation
@@ -60,7 +60,7 @@ print("End 1d\n")
 
 ### 1e multiplication
 print("Start 1e multiplication")
-# intitialization
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 b = Vector([-2, 5, 1, 0, -3])
 # computation with vectors
@@ -77,9 +77,9 @@ y = 0.1 * b.T()
 print(f"0.1 * b.T()= {str(y)} | must be {0.1 * np.array([-2, 5, 1, 0, -3])}")
 print("End 1e\n")
 
-### 1f divison
-print("Start 1f divison")
-# intitialization
+### 1f division
+print("Start 1f division")
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 b = Vector([-2, 5, 1, 7, -3])
 # computation with vectors
@@ -91,7 +91,7 @@ print("End 1f\n")
 
 ### 1g norm
 print("Start 1g norm")
-# intitialization
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 a_norm = a.norm()
 a_normalized = a.normalize()
@@ -101,7 +101,7 @@ print("End 1g\n")
 
 ### 1h negation
 print("Start 1h negation")
-# intitialization
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 x = -a
 print(f"-a = {str(x)} | must be {-np.array([1, 3, 5, 7, 9])}")
@@ -109,7 +109,7 @@ print("End 1h\n")
 
 ### 1i manipulation
 print("Start 1i manipulation")
-# intitialization
+# initialization
 a = Vector([1, 3, 5, 7, 9])
 print(
     f"a[{str([1, 2, 4])}] = {str(np.array(a[1, 2, 4]).reshape(3, ))} | must be {np.array([1, 3, 5, 7, 9]).reshape(5, 1)[np.array([1, 2, 4])].reshape(3, )}")
@@ -148,8 +148,8 @@ print(f"A.T() has shape {A.T().shape()} | must be (3,4)")
 print(f"A.T().T() has shape {A.T().T().shape()} | must be (4,3)")
 print("End 2c\n")
 
-### 1d addition and substraction
-print("Start 2d addition and substraction")
+### 1d addition and subtraction
+print("Start 2d addition and subtraction")
 # Initialization 
 A = Matrix(structure="diagonal", data=[3], offset=0, n=10)
 print(str(A))
@@ -186,8 +186,8 @@ print(
     f"Norm of (B.T()*A.T() - np.(B.T()*A.T())) is {(B.T() * A.T() - Matrix(np.array(b_mat).T @ np.array(a_mat).T)).norm()} | must be < 1e-8")
 print("End 2e\n")
 
-### 1f divison 
-print("Start 2f divison")
+### 1f division 
+print("Start 2f division")
 # initialization
 A = Matrix(a_mat)
 # computation
diff --git a/test/test_vector.py b/test/test_vector.py
index 5ca714f..b31f9b0 100644
--- a/test/test_vector.py
+++ b/test/test_vector.py
@@ -110,7 +110,7 @@ class TestVector(TestCase):
         v = Vector([1, 2])
         s = 5
 
-        expected = Vector([1/5, 2/5])
+        expected = Vector([1 / 5, 2 / 5])
         actual = v / s
 
         self.assertEqual(expected, actual)
@@ -119,7 +119,7 @@ class TestVector(TestCase):
         v1 = Vector([1, 2])
         v2 = Vector([3, 4])
 
-        expected = Vector([1/3, 1/2])
+        expected = Vector([1 / 3, 1 / 2])
         actual = v1 / v2
 
         self.assertEqual(expected, actual)
@@ -274,4 +274,3 @@ class TestVector(TestCase):
         expected = Vector([10, 2, 30, 4, 50, 6, 70, 8, 9])
 
         self.assertEqual(expected, actual)
-