def calculate_mine_count(minefield: list) -> list:
    """
    For each cell in minefield, calculate how many mines are nearby.

    This function cannot modify the original list.
    So, the result should be a new list (or copy of original).

    ....
    ..x.
    X.X.
    x..X

    =>

    0111
    13x2
    X3X3
    x32X

    :param minefield:
    :return:
    """
    new_minefield = deepcopy(minefield)
    x = "x" or "X"
    for index, element in enumerate(new_minefield):
        for second_index, i in enumerate(element):
            count = 0
            if i != element[0]:
                if new_minefield[index][second_index - 1] == x:
                    count += 1
            if i != element[-1]:
                if new_minefield[index][second_index + 1] == x:
                    count += 1
            if element != new_minefield[0] and i != element[0]:
                if new_minefield[index - 1][second_index - 1] == x:
                    count += 1
            if element != new_minefield[0]:
                if new_minefield[index - 1][second_index] == x:
                    count += 1
            if element != new_minefield[0] and i != element[-1]:
                if new_minefield[index - 1][second_index + 1] == x:
                    count += 1
            if element != new_minefield[-1] and i != element[0]:
                if new_minefield[index + 1][second_index - 1] == x:
                    count += 1
            if element != new_minefield[-1]:
                if new_minefield[index + 1][second_index] == x:
                    count += 1
            if element != new_minefield[-1] and i != element[-1]:
                if new_minefield[index + 1][second_index + 1] == x:
                    count += 1
            new_minefield[index][second_index] = str(count)
            if i == x:
                new_minefield[index][second_index] = i
    return new_minefield