Flash dance: multiple out-providers

I have successfully followed the examples in the Flask-Dance documentation to add Oauth from GitHub and manage users with SQLAlchemy. However, I cannot add more vendors. I tried to just add another project for Twitter and register it, but I get various errors when trying to login with Twitter. Also, I get a lot of duplicate code, so this is not a good approach.

Is there a better way to add another vendor?

import sys
from flask import Flask, redirect, url_for, flash, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.orm.exc import NoResultFound
from flask_dance.contrib.github import make_github_blueprint, github
from flask_dance.consumer.backend.sqla import OAuthConsumerMixin, SQLAlchemyBackend
from flask_dance.consumer import oauth_authorized, oauth_error
from flask_login import (
    LoginManager, UserMixin, current_user,
    login_required, login_user, logout_user
)

# setup Flask application
app = Flask(__name__)
app.secret_key = "supersekrit"
blueprint = make_github_blueprint(
    client_id="my-key-here",
    client_secret="my-secret-here",
)
app.register_blueprint(blueprint, url_prefix="/login")

# setup database models
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///multi.db"
db = SQLAlchemy()

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(256), unique=True)
    # ... other columns as needed

class OAuth(db.Model, OAuthConsumerMixin):
    user_id = db.Column(db.Integer, db.ForeignKey(User.id))
    user = db.relationship(User)

# setup login manager
login_manager = LoginManager()
login_manager.login_view = 'github.login'

@login_manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))

# setup SQLAlchemy backend
blueprint.backend = SQLAlchemyBackend(OAuth, db.session, user=current_user)

# create/login local user on successful OAuth login
@oauth_authorized.connect_via(blueprint)
def github_logged_in(blueprint, token):
    if not token:
        flash("Failed to log in with {name}".format(name=blueprint.name))
        return
    # figure out who the user is
    resp = blueprint.session.get("/user")
    if resp.ok:
        username = resp.json()["login"]
        query = User.query.filter_by(username=username)
        try:
            user = query.one()
        except NoResultFound:
            # create a user
            user = User(username=username)
            db.session.add(user)
            db.session.commit()
        login_user(user)
        flash("Successfully signed in with GitHub")
    else:
        msg = "Failed to fetch user info from {name}".format(name=blueprint.name)
        flash(msg, category="error")

# notify on OAuth provider error
@oauth_error.connect_via(blueprint)
def github_error(blueprint, error, error_description=None, error_uri=None):
    msg = (
        "OAuth error from {name}! "
        "error={error} description={description} uri={uri}"
    ).format(
        name=blueprint.name,
        error=error,
        description=error_description,
        uri=error_uri,
    )
    flash(msg, category="error")

@app.route("/logout")
@login_required
def logout():
    logout_user()
    flash("You have logged out")
    return redirect(url_for("index"))

@app.route("/")
def index():
    return render_template("home.html")

# hook up extensions to app
db.init_app(app)
login_manager.init_app(app)

if __name__ == "__main__":
    if "--setup" in sys.argv:
        with app.app_context():
            db.create_all()
            db.session.commit()
            print("Database tables created")
    else:
        app.run(debug=True)