How can you distinguish a class variable from an instance variable?

In Python, variables belonging to a class are called class attributes and are declared inside the class body but outside of methods. They are shared among all instances of the class. Variables associated with a specific object are called instance attributes and are usually created inside methods (for example, in __init__) using self.

Example:

class MyClass:
    class_var = 10  # class attribute

    def __init__(self, value):
        self.instance_var = value  # instance attribute

obj1 = MyClass(1)
obj2 = MyClass(2)

print(MyClass.class_var)      # 10
print(obj1.class_var)         # 10
print(obj1.instance_var)      # 1
print(obj2.instance_var)      # 2

Thus, the class attribute is accessible via the class name and instances, but is shared among all, while the instance attribute is unique to each object.