Python Function for Ordering Lists and Generating Histograms

Here's a possible implementation in Python:

def order_list(lst, ordering):
    if ordering == 'Ascending':
        ordered_list = sorted(lst)
    elif ordering == 'Descending':
        ordered_list = sorted(lst, reverse=True)
    else:
        return 'Invalid ordering parameter'

    histogram = ''
    for num in ordered_list:
        histogram += '>' * num + '\n'

    return histogram

You can use this function to order the list and generate the histogram like this:

lst = [2, 6, 8, 4]
ordering = 'Ascending'
histogram = order_list(lst, ordering)
print(histogram)

Output:

>>
>>>>
>>>>>>
>>>>>>>> 

Note that the function returns 'Invalid ordering parameter' if the ordering parameter is not 'Ascending' or 'Descending'. You can modify this behavior according to your specific needs.