foo

require 'rubygems'
require 'dm-core'
DataMapper.setup(:default, "sqlite3://#{Dir.pwd}/frankie.sqlite3")

class Recipient
  include DataMapper::Resource

  property :id,         Integer, :serial => true
  property :name,       Text
  property :email,      Text, :nullable => false, :unique => true

  def self.get_emails
    all.collect { |recipient| recipient.email }
  end
end

Recipient.get_emails
# => ArgumentError - Unknown property 'get_emails'