docs: def schema(self, hash_key):
          """
          Create the index schema
  
          Parameters
          ----------
          hash_key : :class:`~.DynamoKey`
              The hash key of the table
  
          """
          key_schema = [hash_key.hash_schema()]
          if self.range_key is not None:
              key_schema.append(self.range_key.range_schema())
          schema_data = {
              'IndexName': self.name,
              'KeySchema': key_schema,
              'Projection': {
                  'ProjectionType': self.projection_type,
              }
          }
          if self.include_fields is not None:
              schema_data['Projection']['NonKeyAttributes'] = self.include_fields
          return schema_data