def validate
      begin
        service.report.validate(credentials, to_xml)
        return true
      rescue SoapError => e
        puts e
      end
      return false
    end
def validate
      begin
        service.report.validate(credentials, to_xml)
        return true
      rescue SoapError => e
        puts e
      end
      return false
    end
Validate the report definition to make sure it is valid.
 If it is not, an AdWords::Error::ApiError will be thrown.