class User(Base):
    __tablename__ = "users"

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

    user_keyword_associations = relationship(
        "UserKeywordAssociation",
        back_populates="user",
        lazy="selectin",
    )
    keywords = association_proxy(
        "user_keyword_associations", "keyword", creator=lambda keyword_obj: UserKeywordAssociation(keyword=keyword_obj)
    )

    # I added this simple proxy here.
    keyword_names = association_proxy(
        "user_keyword_associations",
        "name",
    )


class UserKeywordAssociation(Base):
    __tablename__ = "user_keyword"

    user_id = Column(Integer, ForeignKey("users.id"), primary_key=True)
    keyword_id = Column(Integer, ForeignKey("keywords.id"), primary_key=True)

    user = relationship(User, back_populates="user_keyword_associations")
    keyword = relationship("Keyword", lazy="selectin")
    
    # I added this field here.
    name = Column(String)

    # for prevent mypy error: Unexpected keyword argument "keyword" for "UserKeywordAssociation"  [call-arg]
    def __init__(self, keyword: Optional["Keyword"] = None):
        self.keyword = keyword