from datetime import datetime as datetime_sys

import voluptuous


def string(value):
    if value is None:
        raise voluptuous.Invalid("string value is None")
    return str(value)


def datetime(value):
    if isinstance(value, datetime_sys):
        return value
    try:
        return datetime_sys.fromisoformat(value)
    except (TypeError, ValueError) as err:
        raise voluptuous.Invalid("invalid datetime") from err


def config_entry_only_config_schema(domain):
    return lambda config: config