def source_button_action(self):
self.source = pathlib.Path(filedialog.askdirectory())
self.entry_source.config(state='normal')
self.entry_source.delete(0, tkinter.END)
self.entry_source.insert(0, self.source)
self.entry_source.config(state='readonly')
self.source_directory = IO.Directory(self.source)
self.files = self.source_directory.recursvieFileTypeSearch('csv')
self.label_file_count['text']='{} files.'.format(len(self.files))
for i in self.files:
self.file_list.insert(tkinter.END, str(i)+'\n')
self.master.focus()