def list_insert(list l):

    """

    >>> list_insert([1,2,3])

    [1, 4, 2, 3]

    """

    list.insert(l, 1, 4)

    return l

def list_insert_literal():

    """

    >>> list_insert_literal()

    (None, [1, 4, 2, 3])

    """

    l = [1,2,3]

    r = list.insert(l, 1, 4)

    return r, l

def list_insert_assigned():

    """

    >>> list_insert_assigned()

    (None, [1, 4, 2, 3])

    """

    insert = list.insert

    l = [1,2,3]

    r = insert(l, 1, 4)

    return r, l

def list_pop():

    """

    >>> list_pop()

    (2, [1, 3])

    """

    l = [1,2,3]

    r = list.pop(l, 1)

    return r, l

def list_pop_assigned():

    """

    >>> list_pop_assigned()

    [1, 3]

    """

    pop = list.pop

    l = [1,2,3]

    pop(l, 1)

    return l