why I get TypeError when I unpack my **kwargs in python

Question

I have pasted a short portion of my code that is relevant to my question. I am passing a dict to the itemSearch method of my class, but I get a TypeError

def itemsearch(self,*args,**params):
        #items = self.api.item_search('Books', Publisher="O'Reilly", Author="James Shore",Year="2014",limit=10)
        print args
        print params
        itemSearch=self.api.item_search(*args,**params)
        print [item.ASIN for items in itemSearch.Items.Item]
        self.listASIN=[(item.Title,item.ASIN) for items in itemSearch.Items.Item]

amazonsearch=AmazonLookup()
params={'SearchIndex':'Electronics','Condition':'New','Keywords':'Macbook pro 13 retina','MinimumPrice':'600',
        'MaximumPrice':'2000','Sort':'-price'}
print params
amazonsearch.itemsearch(**params)

I get TypeError: item_search() takes at least 2 arguments (1 given)

Answer 1

The problem is in this line:

itemSearch = self.api.item_search(*args, **params)

Apparently, the item_search function requires a positional argument first. Positional arguments are filled from args but args is an empty list as you call the itemsearch function only with a unpacked dictionary:

amazonsearch.itemsearch(**params)

So you need to provide at least that first parameter too (like in your commented-out example: 'Books').