title: How to convert single string and multiple strings to a valid set() in python?
body: <p>Let's assume I read the following strings out of a file:</p>
  <pre><code>s1 = &quot;{'XXX-YYY'}&quot;
  s2 = &quot;{'XXX-YYY', 'XXX-ZZZ', 'XXX-AAA', 'XXX-BBB'}&quot;
  </code></pre>
  <p>I want convert both strings to valid sets. I tried this:</p>
  <pre><code>s1 = {s1}
  s2 = set((s2, ))
  </code></pre>
  <p>The outcome is obviously not a valid set():</p>
  <pre><code>{&quot;{'XXX-YYY'}&quot;}
  {&quot;{'XXX-YYY', 'XXX-ZZZ', 'XXX-AAA', 'XXX-BBB'}&quot;}
  </code></pre>
  <p>It should be:</p>
  <pre><code>{'XXX-YYY'}
  {'XXX-YYY', 'XXX-ZZZ', 'XXX-AAA', 'XXX-BBB'}
  </code></pre>
  <p>How can I achieve this?</p>