Python NameError: name is not defined

Question

I have a python script and I am receiving the following error:

Traceback (most recent call last):
  File "C:\Users\Tim\Desktop\pop-erp\test.py", line 1, in <module>  
  s = Something()
  NameError: name 'Something' is not defined

Here is the code that causes the problem:

s = Something()
s.out()

class Something:
    def out():
        print("it works")

This is being run with Python 3.3.0 under Windows 7 x86-64.

Why can't the Something class be found?

Answer 1

Define the class before you use it:

class Something:
    def out(self):
        print("it works")

s = Something()
s.out()

You need to pass self as the first argument to all instance methods.

Answer 2

You must define the class before creating an instance of the class. Move the invocation of Something to the end of the script.

You can try to put the cart before the horse and invoke procedures before they are defined, but it will be an ugly hack and you will have to roll your own as defined here:

Make function definition in a python file order independent