NameError: name 'Class_Name' is not defined

Question

I have an issue which is I keep getting the error of NameError: name 'Class_Name' is not defined. Which I understand. The tricky part is that my code looks something like this:

class FirstClass():
  second_class: SecondClass
  def __init__(self):
      """SOME CODE HERE"""

class SecondClass(firsClass: FirstClass):
  def __init__(self):
      self.first_class = firstClass

So the problem is that no matter how I arrange the code, I will always have one above the other so it will always say that is not defined. How can I solve this?

------------------------SOLUTION----------------------------

I found the solution to this. If you use the import

from __future__ import annotations

It will read the file and you will be able to call the classes even if they are defined later in the code.

Answer 1

Actually, I found the solution to this.

If we use the import from __future__ import annotations it will read the file and it won't have that problem, so we can reference different things in the order that we want. Taking the example:

class FirstClass():
  second_class: SecondClass
  def __init__(self):
      """SOME CODE HERE"""

class SecondClass(firsClass: FirstClass):
  def __init__(self):
      self.first_class = firstClass

This will be resolved as:

from __future__ import annotations

class FirstClass():
  second_class: SecondClass
  def __init__(self):
      """SOME CODE HERE"""

class SecondClass(firsClass: FirstClass):
  def __init__(self):
      self.first_class = firstClass

You can find more details in the python documentation: https://docs.python.org/3/library/__future__.html