I would like to specify (as a type hint) the currently defined type as the return type from a method.
Here's an example:
class Action(Enum):
ignore = 0
replace = 1
delete = 2
@classmethod
# I would like something like
# def idToObj(cls, elmId: int)->Action:
# but I cannot specify Action as the return type
# since it would generate the error
# NameError: name 'Action' is not defined
def idToObj(cls, elmId: int):
if not hasattr(cls, '_idToObjDict'):
cls._idToObjDict = {}
for elm in list(cls):
cls._idToObjDict[elm.value] = elm
return cls._idToObjDict[elmId]
Ideally I would have liked to specify something like
def idToObj(cls, elmId: int)->Action:
Thank you.
This case is mentioned in official type hints PEP:
When a type hint contains names that have not been defined yet, that definition may be expressed as a string literal, to be resolved later.
class Tree:
def __init__(self, left: Tree, right: Tree):
self.left = left
self.right = right
To address this, we write:
class Tree:
def __init__(self, left: 'Tree', right: 'Tree'):
self.left = left
self.right = right
In your case It would be:
def idToObj(cls, elmId: int)->'Action':
pass # classmethod body