code: def gen_slot_variable(self, cls: ClassDefinition, slotname: str) -> str:
          
          slot = self.schema.slots[slotname]
  
          # Alias allows re-use of slot names in different contexts
          if slot.alias:
              slotname = slot.alias
  
          range_type = self.range_type_name(slot, cls.name)
          # Python version < 3.7 -- forward references have to be quoted
          if slot.inlined and slot.range in self.schema.classes and self.forward_reference(slot.range, cls.name):
              range_type = f'"{range_type}"'
          slot_range, default_val = self.range_cardinality(range_type, slot, cls)
          default = f'= {default_val}' if default_val else ''
          return f'''{underscore(slotname)}: {slot_range} {default}'''
docs: Generate a slot variable for slotname as defined in class