text:  Chesney11,698 Points
  product_sales; reduce()
  Bummer: product_sales threw an exception when given the argument (10.5, 2)
  Treehouse, let's talk about this exception. It doesn't happen on my console
  >>> product_sales(10.5, 2) 21.0 >>>
  prices = [ (6.99, 5), (2.94, 15), (156.99, 2), (99.99, 4), (1.82, 102) ] def product_sales(price, units): return price * units
  1 Answer
  Chris FreemanTreehouse Moderator 67,986 Points
  Your are close. In the directions it says "function named product_sales that takes a single two-member tuple". So instead, you may have:
  def product_sales(tuple_value): price, units = tuple_value # ...
  Chris FreemanTreehouse Moderator 67,986 Points
  Now that
  product_sales is expecting a tuple, it needs to be called with a tuple, such as:
  product_sales((6.99, 5))
  Mark Chesney11,698 Points
  Ah yes, thank you Chris!
  Mark Chesney11,698 Points
  Mark Chesney11,698 Points
  Thanks Chris...
  hmm... now this works to pass step 1 of the challenge, but it throws an error in my console:
  TypeError: product_sales() takes 1 positional argument but 2 were given
  However, if I add the asterisk to make it
  *tuple_value, then this fails the challenge but works on my console.