title: Return a string of country codes from an argument that is a string of prices
body: <p>So here's the question:</p>
  
  <p>Write a function that will return a string of country codes from an argument that is a string of prices (containing dollar amounts following the country codes). Your function will take as an argument a string of prices like the following: <code>"US$40, AU$89, JP$200"</code>. In this example, the function would return the string <code>"US, AU, JP"</code>.</p>
  
  <p>Hint: You may want to break the original string into a list, manipulate the individual elements, then make it into a string again.</p>
  
  <p>Example:</p>
  
  <pre><code>&gt; testEqual(get_country_codes("NZ$300, KR$1200, DK$5")
  &gt; "NZ, KR, DK"
  </code></pre>
  
  <p>As of now, I'm clueless as to how to separate the <code>$</code> and the numbers. I'm very lost.</p>