title: What does the colon inside the parameter mean?
body: <p>What does the colon on words_pron_dict:str mean? I am getting syntax error on python 2.7. Is it python 3? How can i use it?</p>
  
  <pre><code>class TextToSpeech:
      CHUNK = 1024
  
      def __init__(self, words_pron_dict:str = 'cmudict-0.7b.txt'):
          self._l = {}
          self._load_words(words_pron_dict)
  </code></pre>