from typing import List


def _erase_elements_from(items: List, start_i: int):
    """
    Erase from the given 'i' onward

    >>> _erase_elements_from([1, 2, 3], 0)
    [None, None, None]
    >>> _erase_elements_from([1, 2, 3], 1)
    [1, None, None]
    >>> _erase_elements_from([1, 2, 3], 2)
    [1, 2, None]
    >>> _erase_elements_from([1, 2, 3], 3)
    [1, 2, 3]
    """
    items[start_i:] = [None] * (len(items) - start_i)
    # Return the list just for convenience in doctest. It's actually mutable.
    return items