Debugger displays instance with splitted string

Hi,

When I debug the following piece of code the debugger displays the created instance as a splitted string. I figured out that this only occurs with the attribute self.shape. Every other attribute name, like self. shapes, self.unicorn, or self.whatever it does not. 

As far as I know the name “shape” is not a special object in python. So I was wondering why pycharm behave like this?

class Foo:
    def __init__(self, arg):
        self.shape = arg
        print(arg)

bar = Foo("test")