sqlalchemy2-stubs: 'DeclarativeMeta' is not defined

Describe your question When creating a Base class with @as_declarative the following errors shows up using mypy error: Name 'DeclarativeMeta' is not defined. Am I doing something wrong or is there a better way?

Example - please use the Minimal, Complete, and Verifiable guidelines if possible Using the example as provided in the documentation, it works without a problem:

Base = declarative_base()

class User(Base):
    __tablename__ = 'user'

    id = Column(Integer, primary_key=True)
    name = Column(String)

    addresses: Mapped[List["Address"]] = relationship("Address", back_populates="user")

class Address(Base):
    __tablename__ = 'address'

    id = Column(Integer, primary_key=True)
    user_id: int = Column(ForeignKey("user.id"))

    user: Mapped[User] = relationship(User, back_populates="addresses")

main  mypy --config mypy.ini --strict simple-test.py
Success: no issues found in 1 source file

When trying to use it as following it shows the error:

@as_declarative()
class Base(object):
    id = Column(Integer, primary_key=True)


class User(Base):
    __tablename__ = "user"

    name = Column(String)

    addresses: Mapped[List["Address"]] = relationship("Address", back_populates="user")


class Address(Base):
    __tablename__ = "address"

    user_id: int = Column(ForeignKey("user.id"))

    user: Mapped[User] = relationship(User, back_populates="addresses")

main  mypy --config mypy.ini --strict simple-test.py
simple-test.py: error: Name 'DeclarativeMeta' is not defined

mypy config

[mypy]
plugins = sqlalchemy.ext.mypy.plugin

Versions

• OS: MacOS 11.0
• Python: Python 3.9.2
• Mypy: mypy 0.812
• SQLAlchemy: 1.4.3
• sqlalchemy2-stub: 0.0.1a4
• Database: n/a
• DBAPI: n/a