title: Why does asksaveasfilename not return the file type?
body: <p>Tkinter is a great package and filedialog has some very helpful features. Both askopenfilename and asksaveasfilename have the 'filetypes' attribute, but it works differently for each one. </p>
  
  <p>With askopenfilename it provides options in the GUI and returns the filetype, BUT</p>
  
  <p>with asksaveasfilename it only provides options in the GUI and does not return the filetype. Example code is shown below:</p>
  
  <pre><code>import tkinter as tk 
  from tkinter import filedialog 
  
  
  old_file_name = filedialog.askopenfilename(title = "Choose file",filetypes=\
                                         (('All files','*.*'),\
                                          ('tagData','*.tagData'),\
                                          ('FDAX files','*.fdax'),\
                                          ('CSV files','*.csv')))
  
  new_file_name = filedialog.asksaveasfilename(initialdir = "/",filetypes=\
                                           (('tagData','*.tagData'),\
                                            ('FDAX files','*.fdax'),\
                                            ('CSV files','*.csv'),\
                                            ('XLS files','*.xls')))
  
  print(old_file_name)
  print(new_file_name)
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code> C:/Users/christian.abbott/Desktop/FDAX_Error/example.csv
   C:/Users/christian.abbott/Desktop/example
  </code></pre>
  
  <p>I have looked for good filedialog documentation but have not been able to find it. Why does the package behave this way? Is there a better option to extract the full path of a user-prompted file path?</p>