module ActiveFedora::Validations::ClassMethods

def create!(attributes = nil, &block)

so an exception is raised if the record is invalid.
Creates an object just like Base.create but calls save! instead of +save+ 
def create!(attributes = nil, &block)
  if attributes.is_a?(Array)
    attributes.collect { |attr| create!(attr, &block) }
  else
    object = new(attributes)
    yield(object) if block_given?
    object.save!
    object
  end
end