Actually made the code neater.

Trial.py

@@ -1,23 +1,24 @@
+#Imports.
 import bpy;
 
 size = 1;
+numOfCubes = 15;
 x = y = z = size / 2;
 
+#Add starting cube.
 bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));
-#z = 1.5;
-#bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));
 
-#x 
+#Creating cubes in the X-Position. 
-for i in range(15):
+for i in range(numOfCubes):
     x += size;
     bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));
 
-#Z
+#Creating cubes in the Y-Position.    
-for i in range(15): 
+for i in range(numOfCubes):
-    z += size;
-    bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));
-
-#y    
-for i in range(15):
     y += size;
     bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));
+
+#Creating cubes in the Z-Position.
+for i in range(numOfCubes): 
+    z += size;
+    bpy.ops.mesh.primitive_cube_add(size = size, location = (x, y, z));