title: splitting a text file based on paragraphs in python
body: <p>Hi I am trying to split a text file based on paragraphs. I have already split them into a list. However my goal is to extract only those paragraphs which contains just one sentence. Is there any way to do that?</p>
  
  <pre><code>My text file is something like this:
  paragraph1:
  sentence
  paragraph2:
  sentence. sentence. sentence.
  paragraph3:
  sentence. sentence.
  paragraph4:
  sentence
  </code></pre>
  
  <p>I need only 1 and 4 as they have single sentence. I have already done below:</p>
  
  <pre><code>par = document.split(".\n")
  </code></pre>
  
  <p>Which has split the document into a list of paragraphs. But how do I extract only the ones with one sentence. Any ideas?</p>