Why nothing happens when adding a table in Postgresql?

Question

PostgreSQL

I'm trying to create and add a table in Postgresql, but something doesn't work.

create a table

class User(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  usenmr = db.Column(db.String(10), unique=True)

specify the database

app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:[email protected]/testtab'
db = SQLAlchemy(app)

but db.create_all() does nothing. The command is simply accepted, no logs or error messages, just a new line and waiting for a new command. In pgAdmin, the new table does not appear, of course. Tell me what am I doing wrong?