Объясните концепцию метакласса и его роль в определении классов в Python

A metaclass in Python is a class that creates other classes. Simply put, a class is an object, and a metaclass is a "class for classes".

By default, all classes in Python are created using the metaclass type. The metaclass determines how exactly a class is created, what attributes and methods it will have.

The role of a metaclass:

• Manage the process of class creation (for example, automatically adding methods or checking attributes).
• Allow changing the behavior of classes at the stage of their definition.

Example of using a metaclass:

class Meta(type):
    def __new__(cls, name, bases, dct):
        dct['greet'] = lambda self: f"Hello from {name}!"
        return super().__new__(cls, name, bases, dct)

class MyClass(metaclass=Meta):
    pass

obj = MyClass()
print(obj.greet())  # Outputs: Hello from MyClass!

Here, the metaclass adds the greet method to all classes that use it.