title: Function parameter with colon
body: <p>I just came across this function:</p>
  <pre><code>def splitComma(line: str):
      splits = Utils.COMMA_DELIMITER.split(line)
      return &quot;{}, {}&quot;.format(splits[1], splits[2])
  </code></pre>
  <p>I am aware that you can separate parameters by , or can set a value within a parameter like <code>a=39</code> but I have not seen a colon like <code>line:str</code>. I have checked the function definition online but could not find anything like this. What does this colon mean?</p>