class ActionController::Parameters

def except(*keys)

params.except(:d) # => #1, "b"=>2, "c"=>3} permitted: false>
params.except(:a, :b) # => #3} permitted: false>
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