def intersection(l1:list, l2:list) -> list:
    """Calculates the intersection of l1 and l2; l1 ∩ l2

    Parameters
    ----------
    l1 : list
        The first list/set
    l2 : list
        The second list/set

    Returns
    -------
    list
        The list of the intersection between L1 and L2
    """
    result = []
    for value in l1:
            if value in l2:
                    result.append(value)
    return result