title: Counting words in a text file
body: <p>I have .txt file(example):</p>
  
  <blockquote>
    <p>A professional is a person who is engaged in a certain activity, or
    occupation, for gain or compensation as means of livelihood; such as a
    permanent career, not as an amateur or pastime. Due to the personal
    and confidential nature of many professional services, and thus the
    necessity to place a great deal of trust in them, most professionals
    are subject to strict codes of conduct enshrining rigorous ethical and
    moral obligations.</p>
  </blockquote>
  
  <p>How to count how many times there is the word "professional"? (using NLTK - is the best option?)</p>
  
  <pre><code>text_file = open("text.txt", "r+b")
  </code></pre>