title: python raw string assignment
body: <p>Given a file contains lines such as:</p>
  
  <pre><code>(?i:\bsys\.user_catalog\b)
  </code></pre>
  
  <p>While reading those line, I want the value to be a raw string (unescaped), meaning, in memory, line should be </p>
  
  <pre><code>r'(?i:\bsys\.user_catalog\b)'
  </code></pre>
  
  <p>instead of </p>
  
  <pre><code>(?i:\bsys\.user_catalog\b)
  </code></pre>
  
  <p>Which is escaped when passed over to libs such as sqlobject.</p>
  
  <p>For instance, with sqlobject, if I state</p>
  
  <pre><code>Table(column=r'(?i:\bsys\.user_catalog\b)')
  </code></pre>
  
  <p>I get the desired results while if I state</p>
  
  <pre><code>Table(column='(?i:\bsys\.user_catalog\b)')
  </code></pre>
  
  <p>I do not.</p>
  
  <p>So question is basically, I can I pass a raw string when I am not in declarative/assignment mode (e.g. <code>a = r'string'</code>), rather,  the string is already in memory.</p>