attempt to index field 'scalar_steps' (a nil value) when using add_scalar_dict

[twmht]

Hi,

I tried add_scalar_dict as following

local foo = cc:create_experiment("foo")
local d = {}
d['bar'] = 3
d['hoo'] = 4
foo:add_scalar_dict(d)

but got the errors

attempt to index field 'scalar_steps' (a nil value) 

not sure how to use that.

thanks