from sets import Set

class details:
    def __init__(self,fields):
        self.fields= fields

    def __hash__(self):
        return hash(self.fields['key'])

    def __eq__(self,item):
        return self==item                  #<-- tryng some things here, nothing seems to be correct :(

    def __repr__(self):
        return self.fields['key']

tmp = {}
tmp['key'] = 'abcdefg'
tmp['value'] = 34
tmp['name'] = 'Jake'
tmp['foo'] = 'bar'
a = details(tmp)

tmp = {}
tmp['key'] = 'azerty'
tmp['value'] = 12
tmp['name'] = 'Sam'
tmp['foo'] = 'ack'
b = details(tmp)

tmp = {}
tmp['key'] = 'abcdefg'
tmp['value'] = 20
tmp['name'] = 'Mark'
tmp['foo'] = 'Wii'
c = details(tmp)

all = Set([a,b,c])
error = Set([c])

result = all - error

print all
print error
print all - error