lib/createsend/client.rb
def lists_for_email(email_address)
      options = { :query => { :email => email_address } }
      response = get 'listsforemail', options
      response.map{|item| Hashie::Mash.new(item)}
    end
def lists_for_email(email_address)
      options = { :query => { :email => email_address } }
      response = get 'listsforemail', options
      response.map{|item| Hashie::Mash.new(item)}
    end
Gets the lists across a client, to which a subscriber with a particular
 email address belongs.
 email_address - A String representing the subcriber's email address