Return a printable view of the dictionary

def toString(self):
        """
            Return a printable view of the dictionary
        """
        result = []
        k, v = self.optimalRepr()
        longest = reduce(lambda x, y: x if x > len(y) else len(y), k, 0)
        for ind in range(len(k)):
            result.append("%s : %s" % (k[ind].ljust(longest), v[ind]))
        return "\n".join(result)