ama-team / ruby-entity-mapper

        class Normalizer < Interface

          # :nocov:

          # This method takes in provided entity and it's specific type and

          # should return low-level representation of this entity (most

          # commonly, hash of attributes). This normalizer has an option to

          # fall back on default normalization process (using `block.call()`

          # with same signature). Such feature allows to use normalizer as

          # pre- or post-processor, either altering incoming entity or polishing

          # result:

          #

          # ```ruby

          # data = block.call(entity, type, context)

          # data[:parent] = entity.parent.id # replacing parent with it's id

          # data

          # ```

          #

          # It is implied that normalizers *work only on single level*, which

          # means that they should not process underlying attributes. In the

          # example above, that would mean that without additional processing,

          # `data[:parent]` would have parent entity unchanged.

          #

          # @param [Object] entity

          # @param [AMA::Entity::Mapper::Type::Concrete] type

          # @param [AMA::Entity::Mapper::Context] context

          # @param [Proc] block

          # @return [Object]

          def normalize(entity, type, context = nil, &block)

            abstract_method

          end

          # :nocov:

        end