code: def connect(self, database_path, mode="a"):
          
  
          self.close()
  
          logger.debug("connect to a SQLite database: path='{}', mode={}".format(database_path, mode))
  
          if mode == "r":
              self.__verify_db_file_existence(database_path)
          elif mode in ["w", "a"]:
              self.__validate_db_path(database_path)
          else:
              raise ValueError("unknown connection mode: " + mode)
  
          if database_path == MEMORY_DB_NAME:
              self.__database_path = database_path
          else:
              self.__database_path = os.path.realpath(database_path)
  
          try:
              self.__connection = sqlite3.connect(database_path)
          except sqlite3.OperationalError as e:
              raise OperationalError(e)
  
          self.__mode = mode
  
          try:
              # validate connection after connect
              self.fetch_table_names()
          except sqlite3.DatabaseError as e:
              raise DatabaseError(e)
  
          if mode != "w":
              return
  
          for table in self.fetch_table_names():
              self.drop_table(table)
docs: Connect to a SQLite database.
  
          :param str database_path:
              Path to the SQLite database file to be connected.
          :param str mode:
              ``"r"``: Open for read only.
              ``"w"``: Open for read/write.
              Delete existing tables when connecting.
              ``"a"``: Open for read/write. Append to the existing tables.
          :raises ValueError:
              If ``database_path`` is invalid or |attr_mode| is invalid.
          :raises simplesqlite.DatabaseError:
              If the file is encrypted or is not a database.
          :raises simplesqlite.OperationalError:
              If unable to open the database file.