# File lib/new_relic/agent/method_tracer.rb, line 160
          def check_for_illegal_keys!(method_name, options)
            unrecognized_keys = options.keys - ALLOWED_KEYS
            deprecated_keys   = options.keys & DEPRECATED_KEYS

            if unrecognized_keys.any?
              raise "Unrecognized options when adding method tracer to #{method_name}: " +
                    unrecognized_keys.join(', ')
            end

            if deprecated_keys.any?
              NewRelic::Agent.logger.warn("Deprecated options when adding method tracer to #{method_name}: "+
                deprecated_keys.join(', '))
            end
          end