mongodb ex 4.1 and 4.2

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
db = client.Northwind # Get the database

#get a look at which collections are in the database
collection = db.collection_names(include_system_collections=False)
for collect in collection:
   print(collect)

#short name for relevant collections
prod = db['products']
order = db['orders']
ordDet = db['order-details']

#ex 1
relevantOrders = [item['OrderID'] for item in  order.find({"CustomerID": "ALFKI"})]
productAndOrderID = [{k: item[k] for k in ("ProductID", "OrderID")} for item in ordDet.find({'OrderID':{'$in':relevantOrders }})] #order details are extrated for relevant orders

#loop over productsIDs, for each product ID, the dictionary is updatet with the product name taken from the product collection
for item in productAndOrderID:
    prodName = [a['ProductName'] for a in prod.find({'ProductID': item['ProductID']})][0]
    item.update({"productName": prodName})

#print the result
print(*productAndOrderID, sep = "\n")

#ex2
#reuse the detaild order information from ex1 and update with categoryID (completly parallel to ex4.1 where product Name was added)
for item in productAndOrderID:
    catId = [a['CategoryID'] for a in prod.find({'ProductID': item['ProductID']})][0]
    item.update({"CategoryID": catId})

db.ALFKIsOrders.insert(productAndOrderID) #ceate new collection only holding ALFKIs orders

alsOrders= db['ALFKIsOrders'] #and a short name for the new collections

#extract only orderIds which fullfill the criteria (more than two different categoryIDs within the order)
relevantOrdersDiffType = []
for order in range(0,len(relevantOrders)):
    catIds = []
    for item in alsOrders.find({"OrderID": relevantOrders[order]}):
        catIds.append(item['CategoryID'])
        if len(set(catIds)) > 1:
            relevantOrdersDiffType.append(item['OrderID'])

#extract only the relevant orders from ALFKIs order collection
result = [{k: item[k] for k in ("ProductID", "productName","OrderID","CategoryID")} for item in alsOrders.find({'OrderID':{'$in':relevantOrdersDiffType}})]
print(*result, sep = "\n")