title: How to convert 'binary string' to normal string in Python3?
body: <p>For example, I have a string like this(return value of <code>subprocess.check_output</code>):</p>
  
  <pre><code>&gt;&gt;&gt; b'a string'
  b'a string'
  </code></pre>
  
  <p>Whatever I did to it, it is always printed with the annoying <code>b'</code> before the string:</p>
  
  <pre><code>&gt;&gt;&gt; print(b'a string')
  b'a string'
  &gt;&gt;&gt; print(str(b'a string'))
  b'a string'
  </code></pre>
  
  <p>Does anyone have any ideas about how to use it as a normal string or convert it into a normal string? </p>