docs: def get_item(cls, hash_key, range_key=None):
          """ Get item from the table."""
          key = cls._encode_key(hash_key, range_key)
          raw_data = cls._get_connection().get_item(cls.get_table_name(), key)
          if 'Item' not in raw_data:
              raise ItemNotFoundException
          return cls.from_raw_data(raw_data['Item'])