class Person:
def __init__(self, identify: str, deal with: "Handle"):
self.identify = identify
self.deal with = deal with
# ^ as a result of as an example for some motive we will need to have
# an deal with for every consumer
class Handle:
def __init__(self, proprietor: Person, address_line: str):
self.proprietor = proprietor
self.address_line = address_line
This method is beneficial in case you have objects with interdependencies, as within the above instance. There may be in all probability a extra elegant method to untangle it, however not less than you may present ahead-of-time hints in the identical namespace just by offering the identify of the article.
Nevertheless, a greater approach to do that is to make use of a function referred to as deferred analysis of annotations. You should use a particular import to vary the way in which annotations are resolved on the module stage:
from __future__ import annotations
class Person:
def __init__(self, identify: str, deal with: Handle):
self.identify = identify
self.deal with = deal with
# ^ as a result of as an example for some motive we will need to have
# an deal with for every consumer
class Handle:
def __init__(self, proprietor: Person, address_line: str):
self.proprietor = proprietor
self.address_line = address_line
Whenever you add from __future__ import annotations on the high of a module, annotations are actually resolved lazily for that module—simply as in the event that they had been string hints, however the precise object is referred to as a substitute of simply its identify. This enables linters to resolve issues much more powerfully and utterly, which is why it’s the really useful resolution for this drawback. You’ll be able to nonetheless use string hints the place they’re anticipated, however they need to be phased out.
