Fill gradient colorStops

[imomo0]

Is your feature request related to a problem? Please describe.
I would like to be able to set gradient colorStops so that i can gradient my line chart based on yAxis value.

Describe the solution you'd like
The method implemented in java.

Describe alternatives you've considered
Not use gradient.

Additional context
Add any other context or screenshots about the feature request here.

I want to be able to set colorStops to gradient my series based on the value on the yAxis. Like this example.