def last_element(some_list):
    '''return the last element of some_list'''
    if len(some_list) > 0:
        return some_list[-1] # last element
    else:
        return None

def delete_first(some_list):
    '''removes the first element of some_list'''
    del some_list[0]
    
def list_add(some_list, el):
    '''add el to some_list'''
    some_list.append(el)

def second_largest(my_list):
    '''returns the second largest value of my_list'''
    # use a copy so we don't change the original list
    list_copy = my_list.copy()
    list_copy.sort()
    return list_copy[-2]

def last_three(some_string):
    '''returns the last three characters of some_string'''
    return some_string[-3:]