A MarketMaker can run several types of Markets. For example, it can run an hourly real-time market and also an ancillary services market for Regulation.
This is captured by the concept of MarketType. Each MarketType has a unique name, and the list of possible MarketTypes is encoded in the GridWorks enum MarketTypeName.
Additional information about the Market - the duration of the market slots, the duration of gate closing (the time before the start of a MarketSlot by which all bids must be received) - is encapsulated in the MarketType dataclass.