input: 
  import sqlite3
  from flask import Flask, render_template, request, redirect
  
  app = Flask(__name__)
  
  @app.route('/')
  def home():
      return render_template('index.html')
  
  @app.route('/submit', methods=['POST'])
  def submit():
      """
      Submits form data (Name, Email, Phone) to a database and redirects to the home page.
      
      >>> # Assuming the following form data is submitted:
      >>> # Name: John Doe, Email: john.doe@example.com, Phone: 1234567890
      >>> # After submission, the data should be stored in the 'data' table of 'data.db' database.
      >>> # Accessing the home page should render the 'index.html' template.
      """
      name = request.form.get('name')
      email = request.form.get('email')
      phone = request.form.get('phone')
      
      conn = sqlite3.connect('data.db')
      cur = conn.cursor()
      
      cur.execute("INSERT INTO data (name, email, phone) VALUES (?, ?, ?)", (name, email, phone))
      conn.commit()
      
      return redirect('/')
  
  if __name__ == '__main__':
      app.run(debug=True)
  
output:     conn.close()