Как отличить уровни доступа private, protected и public в объектно-ориентированном программировании, и чем они отличаются друг от друга?

In object-oriented programming, access levels determine which parts of the code can access certain class members (variables and methods):

• private — access is allowed only within the class itself. Members with this access level are not accessible from outside and in subclasses.
• protected — access is allowed within the class and its subclasses (inheritants). In Python, this is implemented by convention with a single underscore _, although there is no strict protection.
• public — access is allowed from everywhere, with no restrictions.

Python does not have strict encapsulation, but there are conventions:

• Name without underscores — public.
• Name with a single underscore (_var) — protected (recommended not to use outside the class and its inheritors).
• Name with double underscores (__var) — private, with a name mangling mechanism to make external access more difficult.

Example:

class Example:
    def __init__(self):
        self.public_var = 1
        self._protected_var = 2
        self.__private_var = 3

    def get_private(self):
        return self.__private_var

obj = Example()
print(obj.public_var)        # Accessible
print(obj._protected_var)    # Accessible, but not recommended
# print(obj.__private_var)   # Error
print(obj.get_private())     # Access through class method