how to control formatting of a namedtuple in a list

[Boylan, Ross]

Even after defining custom __str__ and __format__ methods they don't affect the display of objects when they are in a list.  Is there a way to change that, other than explicitly converting each list element to a string?

The last line of output below shows that when I format the list I get standard formatting of my objects instead of my custom format.

Code
#! /usr/bin/python3
from collections import namedtuple

class Foo(namedtuple("Foo", "x")):
    __slots__ = ()

    def __str__(self):
          return "foolish({})".format(self.x)

    def __format__(self, spec):
          return self.__str__()

f=Foo(4)
print(f)
print(str(f))
print("{}".format(f))
print("{}".format([f]))  # a list with one f

Output
foolish(4)
foolish(4)
foolish(4)
[Foo(x=4)]

I'm running Python 3.4.

Thanks.
Ross