flask-admin testing field with length defined

gistfile1.txt

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

import flask_admin as admin
from flask_admin.contrib import sqla

# Create application
app = Flask(__name__)


# Create dummy secrey key so we can use sessions
app.config['SECRET_KEY'] = '123456790'

# Create in-memory database
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:@localhost/test'
db = SQLAlchemy(app)


# Flask views
@app.route('/')
def index():
    return '<a href="/admin/">Click me to get to Admin!</a>'


class Tyre(db.Model):
    __tablename__ = 'tyres'
    tyre_id = db.Column(db.Integer, primary_key=True)
    desc2 = db.Column(db.String(length=10))


class TyreAdmin(sqla.ModelView):
    column_display_pk = True
    form_columns = ['desc2']

# Create admin
admin = admin.Admin(app, name='Example: SQLAlchemy2', template_mode='bootstrap3')
admin.add_view(TyreAdmin(Tyre, db.session))

if __name__ == '__main__':

    # Create DB
    db.drop_all()
    db.create_all()

    # Start app
    app.run(debug=True)