old_contents: import tkinter as tk
  import tk_tools
  
  root = tk.Tk()
  
  kv = tk_tools.KeyValueEntry(
      root, ['key0', 'key1', 'key2'],
      title='help',
      unit_labels=['one', 'two', 'three'],
      defaults=['', 'two', 'three'],
      enables=[True, False, True],
      on_change_callback=lambda: print('works')
  )
  kv.pack()
  
  kv.add_row('key3')
  kv.add_row('key4', enable=False)
  kv.add_row('key5', unit_label='five')
  
  kv.load(
      {
          'key0': '1',
          'key1': '2',
          'key2': '3',
          'key3': '4',
          'key4': '5',
          'key5': '6'
      }
  )
  
  root.mainloop()
  
new_contents: import tkinter as tk
  import tk_tools
  
  
  if __name__ == '__main__':
  
      root = tk.Tk()
  
      key_value = tk_tools.KeyValueEntry(
                  root, ['key0', 'key1', 'key2'],
                  title='help',
                  unit_labels=['one', 'two', 'three'],
                  defaults=['', 'two', 'three'],
                  enables=[True, False, True],
                  on_change_callback=lambda: print('works')
                  )
  
      key_value.pack()
  
      key_value.add_row('key3')
      key_value.add_row('key4', enable=False)
      key_value.add_row('key5', unit_label='five')
  
      key_value.load(
                    {
                        'key0': '1',
                        'key1': '2',
                        'key2': '3',
                        'key3': '4',
                        'key4': '5',
                        'key5': '6'
                    }
                    )
  
      root.mainloop()
  
subject: add if __name__ == '__main__':, renamed variable