Custom List Edit Possibility

We can edit the values inside a Custom list using script. But to create a new custom list is not possible.

Script:
var parentOption = record.load({
type: ‘customlist’,
id: optionDetaildarr[0][“optionInternalID”],
isDynamic: false,
});

var numLines = parentOption.getLineCount({
sublistId: ‘customvalue’
});

parentOption.setSublistValue({
sublistId: “customvalue”,
fieldId: “value”,
value: optionalListValue,
line: numLines
});
parentOption.setSublistValue({
sublistId: “customvalue”,
fieldId: “abbreviation”,
value: optionalListValue,
line: numLines
});
var id = parentOption.save();