input: Write a function to create a Flask application that submits form data containing fields for Name, Email, and Phone, and stores the data in an SQLite database. The function should return True if the data is successfully submitted and stored, otherwise False.
  
  app = None
  
  def submit_form(name, email, phone):
      global app
      if app is None:
          app = Flask(__name__)
  
          @app.route('/')
          def home():
              return render_template('index.html')
  
          @app.route('/submit', methods=['POST'])
          def submit():
              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('/')
          
          app.run(debug=True)
      
      with app.test_client() as client:
          response = client.post('/submit', data={'name': name, 'email': email, 'phone': phone})
          return response.status_code == 302
  
  assert submit_form('John Doe', 'johndoe@example.com', '1234567890') == True
  assert submit_form('Jane Doe', 'janedoe@example.com', '0987654321') == True
  assert submit_form('', 'invalid@example.com', '1234567890') == True
  assert submit_form('John Doe', '', '1234567890') == True
  assert submit_form('Jane Doe', 'janedoe@example.com', '') == True
  assert submit_form('', '', '') == True
output: def submit_form(name, email, phone):
      global app
      if app is None:
          app = Flask(__name__)
  
          @app.route('/')
          def home():
              return render_template('index.html')
  
          @app.route('/submit', methods=['POST'])
          def submit():
              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('/')
          
          app.run(debug=True)
      
      with app.test_client() as client:
          response = client.post('/submit', data={'name': name, 'email': email, 'phone': phone})
          return response.status_code == 302