title: Split an utf-8 encoded string given a bytes offset (python 2.7)
body: <p>Having an utf-8 encoded string like this:</p>
  
  <pre><code>bar = "hello ｡◕‿‿◕｡"
  </code></pre>
  
  <p>and a bytes offset that tells me at which byte I have to split the string:</p>
  
  <pre><code>bytes_offset = 9  
  </code></pre>
  
  <p>how can I split the bar string in two parts resulting in:</p>
  
  <pre><code>&gt;&gt;first_part 
  'hello ｡' &lt;---- #9 bytes 'hello \xef\xbd\xa1'
  &gt;&gt;second_part 
  '◕‿‿◕｡'
  </code></pre>
  
  <p><em>In a nutshell</em>:<br>
  given a bytes offset, how can I transform it in the actual char index position of an utf-8 encoded string?</p>