example-code-2e/23-descriptor/bulkfood/model_v4c.py
2021-09-10 12:34:39 -03:00

14 lines
374 B
Python

# BEGIN MODEL_V4
class Quantity:
def __set_name__(self, owner, name): # <1>
self.storage_name = name # <2>
def __set__(self, instance, value): # <3>
if value > 0:
instance.__dict__[self.storage_name] = value
else:
msg = f'{self.storage_name} must be > 0'
raise ValueError(msg)
# END MODEL_V4