from typing import List
from typing import Any


def deduplicate(a_list: List[Any]) -> List[Any]:
    """
    deduplicate a list

    :param a_list: a list of possibly repeating items
    :returns: a list of unique items
    """
    new_list = []
    for item in a_list:
        if item not in new_list:
            new_list.append(item)
    return new_list