Python

>>> asdf = [1, 2, 3, 4]
>>> asdf[0:0] = [-1, 0]
>>> asdf
[-1, 0, 1, 2, 3, 4]

>>> a = {'a': {'b': 4}}

>>> '{a["a"]["b"]}'.format(a=asdf)
*** KeyError: '"a"'

>>>'{a[a][b]}'.format(a=asdf)
'4'