diff --git a/array2xls/__init__.py b/array2xls/__init__.py
new file mode 100644
index 0000000..4a271a8
--- /dev/null
+++ b/array2xls/__init__.py
@@ -0,0 +1,13 @@
+import tkinter as tk
+
+import gui
+
+
+if __name__ == '__main__':
+    root = tk.Tk()
+    app = gui.Application(master=root)
+    app.mainloop()
+    try:
+        root.destroy()
+    except tk.TclError:
+        pass
\ No newline at end of file
diff --git a/array2xls.py b/array2xls/gui.py
similarity index 86%
rename from array2xls.py
rename to array2xls/gui.py
index 704c181..e2cd678 100644
--- a/array2xls.py
+++ b/array2xls/gui.py
@@ -20,7 +20,7 @@ class StatusBar(tk.Frame):
 
 class Application(tk.Frame):
 
-    def __init__(self, master=None):
+    def __init__(self, master):
         #master.geometry("500x500")
         master.minsize(height=100, width=100)
         tk.Frame.__init__(self, master)
@@ -43,11 +43,4 @@ class Application(tk.Frame):
         print(type(result), ':', result)
         
 
-if __name__ == '__main__':
-    root = tk.Tk()
-    app = Application(master=root)
-    app.mainloop()
-    try:
-        root.destroy()
-    except tk.TclError:
-        pass
+