Some context, I have a similar little more complex function which is under a class, and receives the same error. I do think this is just a concept problem that I have with functions.
Code:
def add(self, atr):
print(self.atr)
add("me")
Error:
Traceback (most recent call last):
File "problem_file_2.py", line 5, in <module>
add("me")
TypeError: add() missing 1 required positional argument: 'atr'
When you have a function under class like one given below, self acts as the context of the instance of the class.
class Number:
def __init__(self, value):
self.value = value
def add(self, atr):
self.value += atr
In order to create an instance, you must call the constructor.
n = Number(5)
n.add(5)
print(n.value)
This will output
10
You are getting the error because you never created the instance.
class A:
def add(self, atr):
self.atr = atr
print(self.atr)
A.add("me") # error
A().add("me") # works
A class is a type. More objects can be of same type.
a=A() makes an object/instance of type A.
self is such an object of type A.
a.add(atr) is like A.add(a,atr).
addseems suspicious since it looks like a function call, not like a method call.