reflect.Value.Convert: value of type reflect.Value cannot be converted to type series.Type

I ran container by `docker run -it -p 8888:8888 -v %CD%:/usr/share/notebooks gopherdata/gophernotes:latest-ds`.
The code below is that I tried to **converting a column into a different type**, it got an error.

I found that the go version in the container is go1.11.4.

However, I ran the same code on my local, it works.
computer info:
* Windows10
* go version: go1.13.4 windows/amd64

Is that any version problem?