What are the differences between creating signals in these two different ways?

问题

Using PySide2, it's possible to create signals in two ways that I know of:

file_changed = Signal()

or

@Signal
def file_changed(self):
    pass

They both seem to do the same thing. What if I want a signal that can emit a value? I know I can do:

file_changed = Signal(str)

...

def load_file(self, file_name):
   self.file_changed.emit(file_name)

But what is the equivalent using the @Signal decorator?

来源：https://stackoverflow.com/questions/57204514/what-are-the-differences-between-creating-signals-in-these-two-different-ways