in lib/twurl/rcfile.rb [108:115]
def <<(oauth_client)
client_from_file = self[oauth_client.username] || {}
client_from_file[oauth_client.consumer_key] = oauth_client.to_hash
(profiles[oauth_client.username] ||= {}).update(client_from_file)
self.default_profile = oauth_client unless default_profile
save
end