class ActionController::Parameters

def except(*keys)

params.except(:d) # => {"a"=>1,"b"=>2,"c"=>3}
params.except(:a, :b) # => {"c"=>3}
params = ActionController::Parameters.new(a: 1, b: 2, c: 3)

filters out the given +keys+.
Returns a new ActionController::Parameters instance that 
def except(*keys)
  new_instance_with_inherited_permitted_status(@parameters.except(*keys))
end