title: Delete all files/directories except two specific directories
body: <p>So, there seems to be a few questions asking about removing files/directories matching certain cases, but I'm looking for the exact opposite:  Delete EVERYTHING in a folder that DOESN'T match my provided examples.</p>
  
  <p>For example, here is an example directory tree:</p>
  
  <pre><code>.
  |-- coke
  |   |-- diet
  |   |-- regular
  |   `-- vanilla
  |-- icecream
  |   |-- chocolate
  |   |-- cookiedough
  |   |-- cupcake
  |   |   |-- file1.txt
  |   |   |-- file2.txt
  |   |   |-- file3.txt
  |   |   |-- file4.txt
  |   |   `-- file5.txt
  |   `-- vanilla
  |-- lol.txt
  |-- mtndew
  |   |-- classic
  |   |-- codered
  |   |-- livewire
  |   |   |-- file1.txt
  |   |   |-- file2.txt
  |   |   |-- file3.txt
  |   |   |-- file4.txt
  |   |   `-- file5.txt
  |   `-- throwback
  `-- pepsi
      |-- blue
      |-- classic
      |-- diet
      `-- throwback
  </code></pre>
  
  <p>I want to delete everything but the files in test/icecream/cupcake/ and test/mtndew/livewire/.  Everything else can go, including the directory structure.  So, how can I achieve this?  Languages I wouldn't mind this being in:  bash or python.</p>