title: Unresolved reference 'pyspark' on pycharm
body: <p>I am a begginer programming in python and I just wanted to import some features from pyspark package. The problem is that, when I write this:</p>
  
  <pre><code>from pyspark.ml.feature import HashingTF, IDF, Tokenizer
  </code></pre>
  
  <p>it is said "Unresolved reference pyspark". Why is that?</p>
  
  <p>Here are the steps I followed to create the proyect:</p>
  
  <ol>
  <li>New project using the interpreter python 3.6</li>
  <li>New python file called    "main.py"</li>
  <li>Once the error pop-up I choose "Install pyspark package" but it does not solve it.</li>
  </ol>
  
  <p>Can anyone help me out please?</p>
  
  <p><a href="https://i.stack.imgur.com/Jo2dr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Jo2dr.png" alt="enter image description here"></a></p>