returns a string representation of the bias details

def get_bias_details(self):
        """
        returns a string representation of the bias details
        """
        res = 'Bias File Details\n'
        for b in self.bias_details:
            if len(b) > 2:
                res += b[0].ljust(35)
                res += b[1].ljust(35)
                res += b[2].ljust(9)
            res += '\n'
        return res