diff --git a/mathgenerator/funcs/set_operation.py b/mathgenerator/funcs/set_operation.py
index 6842efd..370c827 100644
--- a/mathgenerator/funcs/set_operation.py
+++ b/mathgenerator/funcs/set_operation.py
@@ -1,18 +1,16 @@
 from .__init__ import *
 
-
-def set_operation(minval=3,maxval=7,n_a=4,n_b=5):
-    number_variables_a=random.randint(minval,maxval)
-    number_variables_b=random.randint(minval,maxval)
-    a=[]
-    b=[]
+def set_operation(minval = 3, maxval = 7, n_a = 4, n_b = 5):
+    number_variables_a = random.randint(minval, maxval)
+    number_variables_b = random.randint(minval, maxval)
+    a = []
+    b = []
     for i in range(number_variables_a):
-        a.append(random.randint(1,10))
+        a.append(random.randint(1, 10))
     for i in range(number_variables_b):
-        b.append(random.randint(1,10))
-
+        b.append(random.randint(1, 10))
     a=set(a)
     b=set(b)
-    problem= "Given the two sets a=" + str(a) + " ,b=" + str(b) +  ".Find the Union,intersection,a-b,b-a and symmetric difference"
-    solution="Union is " + str(a.union(b)) + ",Intersection is " + str(a.intersection(b)) + ", a-b is "+str(a.difference(b)) + ",b-a is " + str(b.difference(a))+ ", Symmetric difference is "+ str(a.symmetric_difference(b))
-    return problem,solution
+    problem = "Given the two sets a=" + str(a) + " ,b=" + str(b) +  ".Find the Union,intersection,a-b,b-a and symmetric difference"
+    solution ="Union is " + str(a.union(b)) + ",Intersection is " + str(a.intersection(b)) + ", a-b is " + str(a.difference(b)) + ",b-a is " + str(b.difference(a)) + ", Symmetric difference is " + str(a.symmetric_difference(b))
+    return problem, solution