Attributeerror: 'nonetype' Object Has No Attribute 'add'

I got the following error AttributeError: 'NoneType' object has no attribute 'add' while I tried this. not_yet_bought_set = set() . . . for value in set_dict.itervalues(): f

Solution 1:

not_yet_bought_set.add(item)

this will return None and you are assigning it to not_yet_bought_set. So, not_yet_bought_set becomes None now. The next time

not_yet_bought_set = not_yet_bought_set.add(item)

is executed, add will be invoked on None. Thats why it fails.

To fix this, simply do this. Dont assign this to anything.

 not_yet_bought_set.add(item)

Solution 2:

set.add returns nothing.

>>>s = set()>>>the_return_value_of_the_add = s.add(1)>>>the_return_value_of_the_add isNone
True

Replace following line:

not_yet_bought_set = not_yet_bought_set.add(item)

with:

not_yet_bought_set.add(item)