Veneer Project need some hints


I’m currently on project Veneer exercise:

I really have hard time with this project. With walkthrough video I finish 34 tasks.
Now I’m stuck at 35 task, this is what I need to do!

  • Add a wallet instance variable to clients, update the buying and selling of artworks to also exchange dollar amounts.
  • Create a wishlist for your clients, things that are listed but they’re not sure if they should purchase just yet.
  • Create expiration dates for listings! Have out of date listings automatically removed from the marketplace.

If someone can help me with some tips and hints. I don’t look for code, just some tips where I need to start.

this is code from project

class Art:
  def __init__(self, artist, title, medium, year, owner):
    self.artist = artist
    self.title = title
    self.medium = medium
    self.year = year
    self.owner = owner
  def __repr__(self):
      return '{artist}. "{title}". {medium}, {year}. {name}, {location}'.format(artist=self.artist, title=self.title, medium=self.medium, year=self.year,, location=self.owner.location)

class Marketplace:
  def __init__(self):
    self.listings = []
  def add_listing(self, new_listing):
  def remove_listing(self,remove_listing):
  def show_listing(self):
    for lists in self.listings:
class Client:
  def __init__(self, name, location, is_museum, wallet): = name
    self.wallet = wallet
    self.is_museum = is_museum
    if is_museum:
      self.location = location
      self.location = 'Private Collection'
  def sell_artwork(self, artwork, price, wallet):
    if artwork.owner == self:
      new_listing = Listing(artwork, price, self)
  def buy_artwork(self, artwork):
    if artwork.owner != self:
      art_listing = None
      for listing in veneer.listings:
        if == artwork:
          art_listing = listing
    if art_listing != None: = self
class Listing:
  def __init__(self, art, price, seller): = art
    self.price = price
    self.seller = seller
  def __repr__(self):
    return '{n}, {p}'.format(, p=self.price)

veneer = Marketplace()

edytta = Client('Edytta Halpirt', None, False, 0)
moma = Client('The MOMA', 'New york', True, 0)

girl_with_mandolin = Art('Picasso, Pablo', 'Girl with a Mandolin (Fanny Tellier)', 1910, 'oil in canvas', edytta)

edytta.sell_artwork(girl_with_mandolin, '6M (USD)', 100)