def _is_possible_expansion(acro: str, full: str) -> bool:
    """
    Check whether all acronym characters are present in the full form.

    :param acro:
    :param full:
    :return:
    """
    # Empty acronym is presented everywhere
    if not acro:
        return True

    # Non-empty acronym is not presented in empty full form
    if not full:
        return False

    # First char must be the same
    if acro[0].lower() != full[0].lower():
        return False

    j = 0
    # We then skip the first char, as it has already been checked
    for i in range(1, len(acro)):
        j += 1
        while j < len(full):
            if acro[i].lower() == full[j].lower():
                break
            j += 1

    if j < len(full):
        return True

    return False