def investment_term(self, investment_term):
        """ This investment term is in months.  This might change to a relative delta."""
        try:
            if isinstance(investment_term, (str, int)):
                self._investment_term = int(investment_term)
        except Exception:
            raise ValueError('invalid input of investment type %s, cannot be converted to an int' %
                             investment_term)
This investment term is in months.  This might change to a relative delta.