wrong number of arguments (1 for 0)

app/models/page.rb:21:in `delete'
app/models/page.rb:21:in `existing_asset_attributes='
app/models/page.rb:16:in `each'
app/models/page.rb:16:in `existing_asset_attributes='
app/controllers/pages_controller.rb:76:in `update'
app/controllers/pages_controller.rb:75:in `update'

{"commit"=>"Update",
 "_method"=>"put",
 "authenticity_token"=>"5d3b9b14bc062c461bdc64eca48e10c8c17c9d48",
 "id"=>"11",
 "page"=>{"permalink"=>"agaaaaain",
 "name"=>"foo",
 "existing_asset_attributes"=>{"33"=>{"file"=>"/files/33/original/100_0450.JPG?1228809588"},
 "32"=>{"file"=>"/files/32/original/100_0160.JPG?1228809584"}},
 "content"=>"foo"}}