Add python solutions to CRUD workshop challenges

[AfiMaameDufie]

I added the python solutions to the CRUD operations lab.

[dfreniche]

Great work, but some changes are needed, please review. Thanks!

[Jibola]

Non-blocking comments. Things look 100% from dbx-python side.

[AfiMaameDufie]

@dfreniche Hi Diego,
I have made the changes requested.

[dfreniche]

LGTM

[dfreniche]

@AfiMaameDufie this code is not working correctly. The foreignField should be where the book id field is in the reviews collection. In this case, it is in bookId. Also, we're missing a loop to print out the results. My proposed code is:

books_with_reviews = books.aggregate([
  {
    "$lookup":
    {
      "from": "reviews",
      "localField": "_id",
      "foreignField": "bookId",
      "as": "reviews"
    }
  },
  // use this stage to filter only books that have reviews
  {
    "$match": {
      "reviews.0": { "$exists": True }
    }
  }
])

for book in books_with_reviews:
    title = book.get('title')
    reviews = book.get('reviews')
    print(f"Book Title: {title} - Reviews: {reviews}")

Thoughts?