Decorate Value Objects with Input Type Assertion

[harell]

Use decorators on Value Objects such that:

• decorators$assert_input_type checks input arg complies with default value type
• decorators$assert_input_equal_length checks input args are of the same length

See related issue

Cars <- function(model = NA_charater, hp = NA_real_){
 data.frame(model = model, hp = hp)
}

Cars <- decorators$assert_input_type(Cars)
Cars <- decorators$assert_input_equal_length(Cars)