//val urban_deltas = get_deltas(get_prices(List("GOOG", "AAPL"), 2010 to 2012))

def myassert(cond : => Boolean) = {
  try {
    assert(cond)
  } catch { 
    case _ : Throwable => System.exit(1)
  }
}


val ds_urban = List(List(Some(-0.03573991804411003), Some(0.539974575389325)), 
                    List(Some(0.10103414222249969), Some(0.24777764141006836)))



myassert(yearly_yield(ds_urban, 100, 0) == 125)
myassert(yearly_yield(ds_urban, 100, 1) == 117)