KeyError.new

static VALUE
key_err_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE options;

    rb_call_super(rb_scan_args(argc, argv, "01:", NULL, &options), argv);

    if (!NIL_P(options)) {
        ID keywords[2];
        VALUE values[numberof(keywords)];
        int i;
        keywords[0] = id_receiver;
        keywords[1] = id_key;
        rb_get_kwargs(options, keywords, 0, numberof(values), values);
        for (i = 0; i < numberof(values); ++i) {
            if (!UNDEF_P(values[i])) {
                rb_ivar_set(self, keywords[i], values[i]);
            }
        }
    }

    return self;
}