If I understand your question correctly, you should be able to reference class A within class A by putting the type annotation in quotes. This is called forward reference.

class A:
  # do something
  def some_func(self, a: 'A')
  # ...

See ref below

1. https://github.com/python/mypy/issues/3661
2. https://www.youtube.com/watch?v=AJsrxBkV3kc

Yes, as you don't have any other reference to the class from within a static method. You could make these class methods instead, using the classmethod decorator:

class C:
    @staticmethod
    def imstatic():
        print("i'm static")

    @classmethod
    def anotherstatic(cls):
        cls.imstatic()

A class method does have a reference to the class.

You don't need to reference the class inside itself, using bar instead of Test.bar will work fine.

class Test:
    @staticmethod
    def bar():
        pass

    FOO_DICT = {1: bar}


# You can access this outside of the class by simply using Test.FOO_DICT
print(Test.FOO_DICT)

However, there are cases where you really need to use a class in itself. For example

class Test:
    @staticmethod
    def bar():
        pass

    def test_with_other_of_same_instance(self, other: Test):
        print(other.FOO_DICT)

    FOO_DICT = {1: bar}

In this case,

• I want to define a method that accepts an object of the same Test class.
• I want to use python's type hinting to indicate that the expected argument is an instance of Test. This allows me get editor support and also so tools like pylance and mypy can notify me of possible errors if I passed a argument of wrong data type.

As at the time of this writing, I'll get a NameError: name 'Test' is not defined.

This is because by default I can't use a class within itself (It is possible later versions of python will change its default behavior, hence we won't be needing the solution below by that time).

But if you use Python versions from 3.7+ and you can't reference a class within itself, the simple solution came with PEP 563 - Postponed evaluation of annotations. It is implemented by adding a little line of code at the first line of the file

from __future__ import annotations
# other imports or code come afterwards


class Test:
    @staticmethod
    def bar():
        pass

    def test_with_other_of_same_instance(self, other: Test):
        print(other.FOO_DICT)

    FOO_DICT = {1: bar}

So you can use a class within itself in python by simply including that line at the beginning of the file.

Normally, if you use pylance or any similar tool, you get a warning or error display to show you that you imported something and didn't use it. But not in the case of annotations. You don't have to worry about any warning from your editor.

Note that this must occur at the beginning of the file otherwise you get a SyntaxError and versions earlier than 3.7 won't support this.

You need @classmethod rather than @staticmethod - a class method will get passed a reference to the class (where a method will get self), so you can look up attributes on it.

class FooBarBaz:
    BAR = 123

    @classmethod
    def getBar(cls):
        return cls.BAR

You need to store a reference to the object which has the instance of a Y object:

class X(object):
    def __init__(self):
        self.count = 5
        self.y = Y(self) #create a y passing in the current instance of x
    def add2(self):
        self.count += 2

class Y(object):
    def __init__(self,parent):
        self.parent = parent #set the parent attribute to a reference to the X which has it
    def modify(self):
        self.parent.add2()

Example usage:

>>> x = X()
>>> x.y.modify()
>>> x.count
7

You cannot refer to MetaDataElement while it is being constructed, since it does not yet exist. Thus,

class MetaDataElement:
    (MD_INVALID, MD_CATEGORY, MD_TAG) = range(3)
    mapInitiator2Type = {'!':MetaDataElement.MD_CATEGORY, 
                         '#':MetaDataElement.MD_TAG}

fails because the very construction of mapInitiator2Type requires MetaDataElement to have attributes, which it does not yet have. You can think of your constants MD_INVALID, etc. as variables that are local to the construction of your class. This is why the following works, as icktoofay wrote:

class MetaDataElement:
    (MD_INVALID, MD_CATEGORY, MD_TAG) = range(3)
    mapInitiator2Type = {'!': MD_CATEGORY,  # MD_CATEGORY is like a local variable!
                         '#': MD_TAG}

However, you can refer to the class MetaDataElement in any yet un-interpreted piece of code, as in

    def method_of_MetaDataElement(self):
        print MetaDataElement.MD_TAG

You even have to refer to MetaDataElement, here, because MD_TAG is not a kind of local variable when method_of_MetaDataElement() is executed (MD_TAG was only defined as a kind of local variable during class construction). Once the class MetaDataElement is created, MD_TAG is simply a class attribute, which is why method_of_MetaDataElement() must refer to it as such.

You don't need the class name

class SomeClass:
   SOME_CONST = "hello"
   SOME_OTHER_CONST = SOME_CONST + " world"

Use a meta class to automatically set it.

def my_meta(name, bases, attrs):
    cls = type(name, bases, attrs)
    cls.bar = cls
    return cls


class Foo(object):
    __metaclass__ = my_meta


>>> print Foo.bar
<class '__main__.Foo'>

There's no way to refer to the class that's currently being defined. There should really be keywords referring to the current scope, eg. __this_class__ for the innermost class being defined and __this_func__ for the innermost function, so classes and functions can cleanly refer to themselves without having to repeat their name.

You could move the definition of columns out of the class body:

class SomeObject:
    def __init__(self, values):
        self.values = values
    ...

SomeObject.columns = [
    (lambda x: x['type'], 'Type'),
    (lambda x: 'http://localhost/view?id=%s' % x['id'], 'Link'),
    (SomeObject.helper_function, 'Data'),
]

By the way, please always use at least 4-space indentation. Anything less is very hard to read.