from typing import Union
from typing import List


def validate_int(int_input: Union[int, List]) -> List[int]:
    """Checks if input is list.

    :param asset_input: int, list
        Single int or list of ints
    :return List of ints.
    :raises ValueError if input is neither a int or list
    """
    if isinstance(int_input, int):
        return [int_input]
    elif isinstance(int_input, list):
        return int_input
    else:
        raise ValueError("Input should be of type int or list")