Python NameError: name is not defined
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.
Note that sometimes you will want to use the class type name inside its own definition, for example when using Python Typing module, e.g.
class Tree: def __init__(self, left: Tree, right: Tree): self.left = left self.right = rightThis will also result in
NameError: name 'Tree' is not definedThat's because the class has not been defined yet at this point.The workaround is using so called Forward Reference, i.e. wrapping a class name in a string, i.e.
class Tree: def __init__(self, left: 'Tree', right: 'Tree'): self.left = left self.right = right
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: