Pagination algorithm for web applications

pagination.py

def make_pagination(current: int, last: int, delta: int=2) -> list:
    pagination_range = []
    pagination_range_with_dots = []
    left = None

    for i in range(1, last + 1):
        if (i == 1 or i == last
            or i >= current - delta
            and i < current + delta + 1):

            pagination_range.append(i)
    
    for i in pagination_range:
        if left is not None:
            if i - left == 2:
                pagination_range_with_dots.append(left + 1)
            elif i - left != 1:
                pagination_range_with_dots.append('...')

        left = i
        pagination_range_with_dots.append(i)

    return pagination_range_with_dots


print(make_pagination(1, 10)) # [1, 2, 3, '...', 10]
print(make_pagination(6, 15)) # [1, '...', 4, 5, 6, 7, 8, '...', 15]
print(make_pagination(1, 10, delta=3)) # [1, 2, 3, 4, '...', 10]