Require:
1. The object has three attributes: id, host, and port
2. Define the tool create_id, and randomly generate an id for each object during instantiation to ensure that the id is unique
3. Provide two instantiation methods, method 1: the user passes in the host and port Method 2: read the host and port from the configuration file for instantiation
4. Customize the method for the object, save and get_obj_by_id, save can automatically serialize the object into the file, the file path is DB_PATH in the configuration file, the file name is id number, verify whether the object already exists before saving, if it exists, throw an exception , ;get_obj_by_id method is used to deserialize the object from the file