title: Dont know how to solve error : AttributeError: 'str' object has no attribute 'set'
body: <p>I am trying to fetch the result from the OptionMenu when it is clicked. However I keep getting the error.</p>
  
  <pre><code>&gt;Exception in Tkinter callback
  Traceback (most recent call last):
    File "C:\Users\samue\AppData\Local\Programs\Thonny\lib\tkinter\__init__.py", line 1705, in __call__
      return self.func(*args)
    File "C:\Users\samue\AppData\Local\Programs\Thonny\lib\tkinter\__init__.py", line 3440, in __call__
      self.__var.set(self.__value)
  AttributeError: 'str' object has no attribute 'set'
  </code></pre>
  
  <p>I don't know how to solve this as I want to be able to find the value that the user selects so I can use it within another function.</p>
  
  <p>If it helps the words stored in the database are city names.</p>
  
  <pre><code>def destination_selected() :
      selection = destination_choice.get()
      print(selection)
  
  def destination_dropdownbox_GUI():
      destination = []
      cursor.execute('SELECT DISTINCT Destination FROM FlightTable ')
      row = str(cursor.fetchone())
      x = 0
      for x in row :
          row = str(cursor.fetchone())
          row = re.sub(r'\W+', '', row)
          destination.append(row)
          if row == 'None' :
              break
      destination.pop()
      print(destination)
      temp_dest = []
      temp_dest = destination
      print(temp_dest)
      destination_dropdownbox = OptionMenu(window, *temp_dest,command = destination_selected).pack()
  </code></pre>
  
  <p>I expect an output of a city name. EG <code>'Oslo'</code></p>