Modelのカラム名でアクセスするとNoMethodError

Modelのカラム名にうっかりclassとか付けちゃうとカラム名でアクセスしたとき例外が出て詰みます

testmodel

class CreateTestmodels < ActiveRecord::Migration
  def self.up
    create_table :testmodels do |t|
      t.string :name
      t.integer :class

      t.timestamps
    end
  end

  def self.down
    drop_table :testmodels
  end
end

実行

$rails c
Loading development environment (Rails 3.0.5)
ruby-1.9.2-p180 :001 > m = Testmodel.new
 => #<Testmodel id: nil, name: nil, class: nil, created_at: nil, updated_at: nil> 
ruby-1.9.2-p180 :002 > m.name = "aaa"

例外

NoMethodError: undefined method `private_method_defined?' for nil:NilClass
	from /Users/user/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/whiny_nil.rb:48:in `method_missing'
	from /Users/user/.rvm/gems/ruby-1.9.2-p180/gems/activemodel-3.0.5/lib/active_model/attribute_methods.rb:403:in `guard_private_attribute_method!'
	from /Users/user/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.5/lib/active_record/attribute_methods.rb:43:in `method_missing'