def count_unique(list):
    """Count the number of distinct elements in a list.

    The list can contain any kind of elements, including duplicates and nulls in any order.

    (In PyDoc there are different formats for parameters and returns. Use what you prefer.)

    :param list:  list of elements to find distinct elements of
    :return: the number of distinct elements in list

    Examples:
    >>> count_unique(['a','b','b','b','a','c','c'])
    3
    >>> count_unique(['a','a','a','a'])
    1
    >>> count_unique([ ])
    0
    """
    if(list == null): 
        return 0 
    return len(set(list))


