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


def second_largest(my_list):
    '''Return the second largest value in my_list
    Example: second_largest([3, 10, 2, 1]) should be 3
    '''
    copy_list = my_list.copy() 
    copy_list.sort() # sort a copy of the last, not the original list
    return copy_list[-2]


def last_three(some_string):
    '''Returns the last 3 characters of some_string
    Example: last_three('computer') should return 'ter'
    '''
    return some_string[-3:]


def print_squared_list(some_list):
    '''Print every element of some_list squared.'''
    for list_el in some_list:
        print(list_el ** 2)
        

def print_negative_nums(some_list):
    '''Print only the negative elements of some_list.
    Example: print_negative_nums([5, -3, -7, 2]) should print -3 and -7'''
    for num in some_list:
        if num < 0:
            print(num)


def get_negative_nums(some_list):
    '''Return a list of all the negative elements of some_list.
    Example: print_negative_nums([5, -3, -7, 2]) should return [-3, -7]'''
    negative_so_far = [] # make an empty list
    for num in some_list:
        if num < 0:
            negative_so_far.append(num)
    # after running the complete loop, return the result list
    return negative_so_far


def list_length(some_list):
    '''Return the length of some_list without using len.'''
    count = 0 # running counter
    for element in some_list:
        count += 1
    # after completion of the loop
    return count