[FEAT] Improve Bernstein Function representation about rmo HOT 1 OPEN

setClass(
    "VectorBernsteinFunction",
    contains = "BernsteinFunction",
    slots = c(
        coefficients = "numeric",
        basis = "list"              ## list of basis Bernstein functions
    )

setValidity(
    "VectorBernsteinFunction",
    function(object) {
        if (!qtest(object@coefficients, "N+(0,)")) {
            return(error_msg_domain("coefficients", "N+(0,)"))
        }
        if (!test_list(object@basis, types = "BasisBernsteinFunction", any.missing = FALSE, len = length(coefficients))) {
            return(error_msg_domain("basis")
        }

        invisible(TRUE)
    })