def create(opts)
      raise "You must set either :PhoneNumber or :AreaCode" if !opts.include?(:AreaCode) && !opts.include?(:PhoneNumber)
      Twilio.post("/IncomingPhoneNumbers", :body => opts)
    end
def create(opts)
      raise "You must set either :PhoneNumber or :AreaCode" if !opts.include?(:AreaCode) && !opts.include?(:PhoneNumber)
      Twilio.post("/IncomingPhoneNumbers", :body => opts)
    end
Creates a phone number in Twilio. You must first find an existing number using
 the AvailablePhoneNumber class before creating one here.

 Required: you must either set PhoneNumber or AreaCode as a required option
 For additional options, see http://www.twilio.com/docs/api/rest/incoming-phone-numbers