Where are described "darktable" functions ? (solved)

In any lua script we have basic declarations like this
local dt = require “darktable”
local du = require “lib/dtutils”
local df = require “lib/dtutils.file”
local dtsys = require “lib/dtutils.system”

Here darktable lua documentation - overview we have dtutils functions described but where can I find descrition about “darktable” functions like database.import, configuration.running_os ?

I new I am stupid.
I found.