input: Write a function to store and query user data in a JSON file. The function should accept a dictionary containing user information and store it in a file named 'user_data.json'. The function should also be able to retrieve and return the user data from the JSON file. If the file does not exist or is empty, the function should return an empty dictionary.
  assert store_user_data({"Name": "John", "Age": 25, "City": "New York"})==None
  assert get_user_data()=={"Name": "John", "Age": 25, "City": "New York"}
output: def store_user_data(user_info):
      try:
          with open('user_data.json', 'r') as file:
              data = json.load(file)
      except (FileNotFoundError, json.JSONDecodeError):
          data = {}
      data.update(user_info)
      with open('user_data.json', 'w') as file:
          json.dump(data, file)
  
  def get_user_data():
      try:
          with open('user_data.json', 'r') as file:
              return json.load(file)
      except (FileNotFoundError, json.JSONDecodeError):
          return {}