I’m using Horizontal Scroll plugin. There’s a default key combination - “alt + up/down” but it’s not so convenient. That’s why I’m trying to set my own combination.
Something like this but I guess this is not the right way to write this 
{ "keys": "alt+scroll_up"], "command": "scroll_width", "args": {"amount": 30 } },
{ "keys": "alt+scroll_down"], "command": "scroll_width", "args": {"amount": -30 } }
]