title: what is "foo" used for in "def function(foo):" when using Python3.x
body: <p>Hello I'm just wondering about something in Python3.x.</p>
  
  <p>What is the <code>foo</code> in <code>def function(foo):</code> used for when you can use <code>def function():</code> too?</p>
  
  <p>I know there is a difference, I just don't understand the definitions I have found in various books and tutorials.</p>