title: data format for fasttext python
body: <p>I want to build and test classifier. 
  I made 2 files - train.txt and test.txt</p>
  
  <hr>
  
  <p>train.txt/test.txt</p>
  
  <hr>
  
  <p>__label__1 , (text)\n</p>
  
  <hr>
  
  <p>__label__2 , (text)\n</p>
  
  <hr>
  
  <p>__label__3 , (text)\n</p>
  
  <hr>
  
  <p>and so on. After building a classifier:</p>
  
  <pre><code>classifier = fasttext.supervised("train.txt","model")
  </code></pre>
  
  <p><code>result = classifier.test("test.txt")</code></p>
  
  <p>The precision is always 1/n (n - number of lines). So the classifier is for every input returning the same entity (for example 2 for all inputs). </p>