diff --git a/src/repositories/InMemoryParkingRepository.ts b/src/repositories/InMemoryParkingRepository.ts
index 763ab38..a23a886 100644
--- a/src/repositories/InMemoryParkingRepository.ts
+++ b/src/repositories/InMemoryParkingRepository.ts
@@ -1,36 +1,44 @@
 import { ParkingGetterSetterRepository } from "./ParkingGetterSetterRepository";
-import { IParkingStructure } from "../entities/ParkingRepositoryEntities";
+import {
+  IParkingStructure,
+  IParkingStructureTimestampRecord
+} from "../entities/ParkingRepositoryEntities";
+import { HistoricalParkingAverageQueryResult } from "./ParkingGetterRepository";
+
+type ParkingStructureID = string;
 
 export class InMemoryParkingRepository implements ParkingGetterSetterRepository {
-  private structures: Map<string, IParkingStructure>;
-
-  constructor() {
-    this.structures = new Map<string, IParkingStructure>();
+  constructor(
+    private structures: Map<ParkingStructureID, IParkingStructure> = new Map(),
+    private historicalData: Map<ParkingStructureID, IParkingStructureTimestampRecord[]> = new Map(),
+  ) {
   }
 
-  async addOrUpdateParkingStructure(structure: IParkingStructure): Promise<void> {
+  addOrUpdateParkingStructure = async (structure: IParkingStructure): Promise<void> => {
     this.structures.set(structure.id, { ...structure });
-  }
+  };
 
-  async clearParkingStructureData(): Promise<void> {
+  clearParkingStructureData = async (): Promise<void> => {
     this.structures.clear();
-  }
+  };
 
-  async getParkingStructureById(id: string): Promise<IParkingStructure | null> {
+  getParkingStructureById = async (id: string): Promise<IParkingStructure | null> => {
     const structure = this.structures.get(id);
     return structure ? { ...structure } : null;
-  }
+  };
 
-  async getParkingStructures(): Promise<IParkingStructure[]> {
-    return Array.from(this.structures.values()).map(structure => ({ ...structure }));
-  }
+  getParkingStructures = async (): Promise<IParkingStructure[]> => Array.from(this.structures.values()).map(structure => ({...structure}));
 
-  async removeParkingStructureIfExists(id: string): Promise<IParkingStructure | null> {
+  removeParkingStructureIfExists = async (id: string): Promise<IParkingStructure | null> => {
     const structure = this.structures.get(id);
     if (structure) {
       this.structures.delete(id);
       return { ...structure };
     }
     return null;
-  }
+  };
+
+  getHistoricalAveragesOfParkingStructureCounts = async (id: string): Promise<HistoricalParkingAverageQueryResult[]> => {
+    return [];
+  };
 }