# File lib/jira/base.rb, line 197
    def self.has_one(resource, options = {})
      attribute_key = options[:attribute_key] || resource.to_s
      child_class = options[:class] || ('JIRA::Resource::' + resource.to_s.classify).constantize
      define_method(resource) do
        attribute = maybe_nested_attribute(attribute_key, options[:nested_under])
        return nil unless attribute
        child_class.new(client, :attrs => attribute)
      end
    end