title: python regular expression, cut multiple line
body: <p>Have read <code>re.M</code> but still no idea how to achieve this (in reasonable approach)</p>
  
  <p>Source string is:</p>
  
  <pre><code>'ClassId=A1\n    classname=A1\n   \nClassId=B1\n    classname=B1\n '
  </code></pre>
  
  <p>Question is how to split it to two elements list below:</p>
  
  <pre><code>targe[0]='ClassId=A1\n    classname=A1'
  targe[1]='ClassId=B1\n    classname=B1'
  </code></pre>