input: Write a function to create a Flask application that submits form data containing Name, Email, and Phone and stores it in a SQLite database named 'data.db'. The database should have a table named 'data' with columns 'name', 'email', and 'phone'. The function should return the Flask application.
  assert create_flask_app() is not None
  assert type(create_flask_app()) is Flask
output: def create_flask_app():
      from flask import Flask, request, render_template_string
      import sqlite3
  
      app = Flask(__name__)
  
      conn = sqlite3.connect('data.db')
      cursor = conn.cursor()
      cursor.execute('''
          CREATE TABLE IF NOT EXISTS data (
              name TEXT,
              email TEXT,
              phone TEXT
          )
      ''')
      conn.commit()
      conn.close()
  
      @app.route('/submit', methods=['POST'])
      def submit():
          name = request.form['name']
          email = request.form['email']
          phone = request.form['phone']
  
          conn = sqlite3.connect('data.db')
          cursor = conn.cursor()
          cursor.execute('INSERT INTO data (name, email, phone) VALUES (?, ?, ?)', (name, email, phone))
          conn.commit()
          conn.close()
  
          return 'Data submitted successfully'
  
      return app