why not "'in' in 'in'"?

[jepler at unpythonic.net]

If
    'in' in 'in' == 1
then what about
    [1, 2] in [1, 2]
?  How do you tell that situation from
    [1, 2] in [[1, 2]]
?

The members of a string are characters, not arbitrary substrings.

Jeff