python - What does "self.default = default if default else type()" mean? -

i have been .net guy since started working (~6 years). recently, working on project using django, requires me learn python in parallel. lot of times bumped python code looked simple couldn't understand. , here 1 of them.

class typedproperty(object):     def __init__(self, name, type, default=none):         self.name = "_" + name         self.type = type         self.default = default if default else type() 

can kindly explain me last line of code doing?

i hope question not trivial, having trouble coming title it.

a if b else c conditional expression evaluates a if b evaluates true, , c otherwise. in given context, checks if default "trucy", in case stored in self.default. otherwise, new instance of type created , stroed in self.default.

note implementation has several issues:

1. it uses type variable name, shadowing built-in type(). considered bad style.

2. it uses condition if default if default none should used. check intended test if parameter default passed constructor. is, implementation won't accept default value evaluates false.