Simple web app

hello.py

import os
import sqlite3

from flask import Blueprint, Flask, current_app, g, render_template, request

# manually set instance dir
app = Flask(__name__, instance_path='/home/../simple/instance') 
app.config.from_mapping(
    DATABASE=os.path.join(app.instance_path, 'simple.sqlite')
    )


def get_db():
    if 'db' not in g:
        g.db = sqlite3.connect(
            current_app.config['DATABASE'],
            detect_types=sqlite3.PARSE_DECLTYPES
        )
        g.db.row_factory = sqlite3.Row

    return g.db


def close_db(e=None):
    db = g.pop('db', None)

    if db is not None:
        db.close()


def RepresentsInt(s):
    try:
        int(s)
        return True
    except ValueError:
        return False


@app.route('/', methods=('GET', 'POST'))
def hello():
    if request.method == 'POST':
        enter_value = request.form['value']
        if RepresentsInt(enter_value):

            db = get_db()
            error = None
            if error is None:
                db.execute(
                    'INSERT INTO post (value) VALUES (?)', (enter_value,)
                )
                db.commit()
                return render_template('index.html')
        else:
            return 'enter int'
        flash(error)
    return render_template('index.html')