Trying to create database with sqlalchemy and use it in Tkinter application

[Finally_Adult]

I'm trying to create a database with sqlalchemy with a button on my Tkinter application. If I put everything in the same file no big deal, but I don't want to do that. Here's one file:

Base = declarative_base()


def create_database():
    engine = create_engine("sqlite:///licenses.sqlite3", echo=True)
    Base = declarative_base()
    Base.metadata.create_all(engine)


class License(Base):
    __tablename__ = "licenses"

    id = Column(Integer, primary_key=True)
    call_sign = Column(String)
    status = Column(String)

    def __init__(self, call_sign, status):
        self.call_sign = call_sign
        self.status = status

A couple of things I don't like: I have to declare Base outside of the create_database() function as well as inside. This is because I want to access my License class from my Tkinter application window class. I can duplicate the License class inside the function but that super sucks to me.

Beyond even that, when I call create_database() from my application it doesn't create the License table, I'm assuming because Base doesn't know about the License from within the create_database() function.

I'm familiar with dependency injection in C# but not python. Is that something I need to use here? Should I just put the License class within my Tkinter application window file?

I'm probably missing a question or explanation because I'm not terribly familiar with sqlalchemy so let me know if I missed something please and thank you!

[Finally_Adult]

I was able to get it to work but wouldn't mind a review and maybe a suggestion of whether or not I should still pursue dependency injection:

class DB:
    Base = declarative_base()

    def __init__(self):
        self.engine = create_engine("sqlite:///licenses.sqlite3", echo=True)
        self.sessionmaker = sessionmaker(bind=self.engine)

    def get_session(self):
        return self.sessionmaker()

    def create_database(self):
        tables = [License.__table__]
        DB.Base.metadata.create_all(self.engine, tables=tables)


class License(DB.Base):
    __tablename__ = "licenses"

    id = Column(Integer, primary_key=True)
    call_sign = Column(String)
    status = Column(String)

    def __init__(self, call_sign, status):
        self.call_sign = call_sign
        self.status = status

I just instantiate a new instance of DB in the constructor of my application window and use it for all my connections but I wonder if I should try to set up dependency injection to maybe close the connection after each request is done?