beginner question

[Qiang.JL]

for this line:

>>> g=(lambda x: ' '.join(x.split())) or (lambda y: 'second')

now by calling g(str(something)) make sure i always pass a string to the
function(ignore exception if improper stuff in str). I want to know what
parameter i can pass to the lambda function so that the first condition
false then second condition get executed?
or as long as i pass a string,it's always true for the first condition?

Q.