'Initialize a Consumer instance.
You should create a new instance of the Consumer object with
every HTTP request that handles OpenID transactions.
@param session: See L{the session instance variable<openid.consumer.consumer.Consumer.session>}
@param store: an object that implements the interface in
C{L{openid.store.interface.OpenIDStore}}.  Several
implementations are provided, to cover common database
environments.
@type store: C{L{openid.store.interface.OpenIDStore}}
@see: L{openid.store.interface}
@see: L{openid.store}'

def __init__(self, session, store, consumer_class=None):

    self.session = session
    if (consumer_class is None):
        consumer_class = GenericConsumer
    self.consumer = consumer_class(store)
    self._token_key = (self.session_key_prefix + self._token)
