How to handle creating schema/tables on the fly for a multi-tenant web app

Problem

I'm building a web app, where each user needs to have segregated data (due to confidentiality), but with exactly the same data structures/tables.

Looking around I think this concept is called multi-tenants? And it seems as though a good solution is 1 schema per tenant.

I think sqlalchemy 1.1 implemented some support for this with

session.connection(execution_options={
    "schema_translate_map": {"per_user": "account_one"}})

However this seems to assume the schema and tables are already created.

I'm not sure how many tenants I'm going to have, so I need to create the schema, and the tables within them, on the fly, when the user's account is created.

Solution

What I've come up with feels like a bit of a hack, which is why I'm posting here to see if there's a better solution.

To create schemas on the fly I'm using

if not engine.dialect.has_schema(engine, user.name):
   engine.execute(sqlalchemy.schema.CreateSchema(user.name))

And then directly afterwards I'm creating the tables using

table = TableModel()
table.__table__.schema = user.name
table.__table__.create(db.session.bind)

With TableModel defined as

class TableModel(Base):

    __tablename__ = 'users'

    __table_args__ = {'schema': 'public'}

    id = db.Column(
        db.Integer,
        primary_key=True
    )

    ...

I'm not too sure why to inherit from Base vs db.Model - db.Model seems to automatically create the table in public, which I want to avoid.

Bonus question

Once the schema are created, if, down the line, I need to add tables to all the schema - what's the best way to manage that? Does flask-migrations natively handle that?

Thanks!