title: "TypeError: bad argument type for built-in operation"
body: <p>In what cases would Python throw this error:</p>
  
  <pre><code>"TypeError: bad argument type for built-in operation"
  </code></pre>
  
  <p>The error was reported in this line of code:</p>
  
  <pre><code>csv.reader(open(file_name), dialect=dialect)
  </code></pre>
  
  <p>I've tried to reproduce it but the closest I got was this error:</p>
  
  <pre><code>"TypeError: coercing to Unicode: need string or buffer, bool found"
  </code></pre>
  
  <p>I've tried with Python2.7 and Python 2.5 on Linux and Python 2.4 on Windows XP</p>