Set colors of multiple isosurfaces

Iā€™m looking for advice on how to set the colors of multiple isosurfaces which have been added using .add_trace, i.e.:

import plotly.graph_objects as go
fig = go.Figure()
zone1 = go.Isosurface( ... )
zone2 = go.Isosurface( ... )
fig.add_trace(zone1)
fig.add_trace(zone2)

So for this example, how would I color zone1 as red, zone2 as blue?

EDIT
Actually, I figured out a way to do it. I simply inserted a custom monochromatic colorscale into each of the go.Isosurface object creations for zone1 and zone 2, e.g.

zone1 = go.Isosurface(
    ...
    colorscale=['red','red'],
    ...
)