module Sequel::Plugins::OptimisticLocking

def self.apply(model, opts=OPTS)

Load the instance_filters plugin into the model. 
def self.apply(model, opts=OPTS)
  model.plugin :instance_filters
end

def self.configure(model, opts=OPTS)

that option is not given.
Set the lock_column to the :lock_column option, or :lock_version if 
def self.configure(model, opts=OPTS)
  model.lock_column = opts[:lock_column] || :lock_version
end