Method parameter type refering to the class it's defined in is causing AttributeError partially initialized module

Question

I have a dataclass in extensions > __init__.py like:

@dataclass
class Range:
    start: date
    end: date

    def overlap(self, other: Range) -> bool:
      # method body removed

My IDE is complaining about the method parameter

Unresolved reference 'Range' 

If I change the parameter type to

def overlap(self, other: extensions.Range) -> bool:

IDE stops complaining but when I run my program I get

partially initialized module 'extensions' has no attribute 'Range' (most likely due to a circular import)

I'm learning Typing in python and cannot figure out how to define this type in my method

Answer 1

I think this has been asked before. You can use a forward reference in the form of a string.

@dataclass
class Range:
    start: date
    end: date

    def overlap(self, other: 'Range') -> bool:
        pass