docs: def linked_attribute(self):
          """Choose the Linkage attribute between `via` and designated `id_field` of the target class
  
          This method is initially called from `__set_name__()` -> `get_attribute_name()`
          at which point, the `to_cls` has not been initialized properly. We simply default
          the linked attribute to 'id' in that case.
  
          Eventually, when setting value the first time, the `to_cls` entity is initialized
          and the attribute name is reset correctly.
          """
          if isinstance(self.to_cls, str):
              return 'id'
          else:
              return self.via or self.to_cls.meta_.id_field.attribute_name