title: Python - Determine overlaps of 3 ranges
body: <p>I had a question regarding how I should go about determining overlaps of three ranges in Python without using any existing libraries :</p>
  
  <p>For instance if I have three ranges as (10,20)(15,25)(18,30), how should I go about finding overlaps between them ? </p>
  
  <p>My answer should be (18,19,20) </p>
  
  <p>Any help would be much appreciated. Thanks ! </p>