What is the scope of a variable inside a class and how is it determined?

In Python, the protected modifier is implemented by convention — the name of the method or attribute starts with an underscore _. This indicates that the method or attribute is intended for internal use within the class and its subclasses, not for external use.

Unlike Java, Python does not enforce access restrictions; it is only a developer convention.

Example:

class Base:
    def _protected_method(self):
        print("This is a protected method")

class Derived(Base):
    def access_protected(self):
        self._protected_method()  # correct

obj = Derived()
obj.access_protected()
# obj._protected_method()  # technically possible, but not recommended

Thus, protected methods help indicate internal implementation details that are not meant for public API.