How can I set the path to Instruments on Appium

How can I set the path to Instruments on Appium

I'm trying to run Appium for an iOS application, but it seems that the
path to instruments is invalid. How can I set it? Is there an environment
variable I should use? Or some argument? Even I could change that in the
source code it would be useful for me :)
Here's the relevant part of the log I receive from Appium:
debug: Creating instruments info: instruments is: info: [INSTSERVER]
Instruments socket server started at /tmp/instruments_sock info: Spawning
instruments with command: -t
/usr/local/lib/node_modules/appium/app/uiauto/Automation.tracetemplate
/var/folders/rd/z5t93lfj0cx0wm2_hqmthnkr0000gn/T/TestApp.app -e UIASCRIPT
/usr/local/lib/node_modules/appium/app/uiauto/bootstrap.js -e
UIARESULTSPATH /tmp/appium-instruments/
Thanks!