<prompt> Human: Hello, I keep part of my savings in a lazy equity portfolio consisting of a mixture of domesticinternational index funds. Previously, I have used Betterment, which for a fee automatically invests money into an optimized mixture of various index funds like VTI, VWO, BND, etc.I wondered whether I could do this balancing myself, and so I wrote a simple script in Python on GitHub here that, given an amount of money to invest and a desired stock allocation like 70 VTI, 30 VXUS and the current allocation in your portfolio, calculates how many shares of each equity to buy in order to keep your portfolio balanced. In principal, this could be used to do more sophisticated allocations like those advertised by robobrokers like Betterment.I am posting it here in case it is helpful to anyone---please feel free to recommend featuresimprovement to add or to directly submit pull requests.  <response>: Thank you for sharing. This is very helpful. 