@staticmethod
def max(a, b):
    """ Generates the expression max(a, b) to insert on GEE expression

        :param a: one value to compare
        :param b: the other value to compare
        :return: expression
        :rtype: str
        """
    exp = '({a}>{b}?{a}:{b})'.format(a=a, b=b)
    return exp
