Make a function name first_and_last_4 that accepts an iterable and returns the first 4 and last 4 items in the iterable.

Three errors with the function first_and_last_4().

• The functions first_4() and last_4() need to be passed arguments:
• extend() only works on lists and not on strings, so if a string iterable were passed to first_and _last_4() it would fail with an AttributeError: str has no attribute extend
• If passed an actually list, extend() operates on a list "in place", that is the output of first_4, which would be a list, is assigned to a temporary unnamed variable. Then extend alters this variable in place, but does not return a value. There is no value to be returned.

Ignoring the string input issue (not sure if you are asking about that aspect), see updated code below:

def first_4(x):
    return x[0:4]

def odds(x):
    return x[1::2]

def last_4(x):
    return x[-4:]

def first_and_last_4(x): 
    result = first_4(x)
    result.extend(last_4(x))
    return result

or alternatively, just add the resultant parts:

def first_and_last_4(x): 
    return first_4(x) + last_4(x)