[Bug] pydeck get_fill_color expression parser only if first element is str

Description

I can use pydeck get_fill_color expression parser only if the first element is str type.
get_fill_color=["lng > 0 ? 255 : 88", "lng > 0 ? 255 : 88", "lng > 0 ? 255 : 88"], -> OK
get_fill_color=["255", "lng > 0 ? 255 : 88", "lng > 0 ? 255 : 88"], -> OK
get_fill_color=[255, "lng > 0 ? 255 : 88", "lng > 0 ? 255 : 88"], -> Not OK

Flavors

• React
• Python/Jupyter notebook
• MapboxLayer
• GoogleMapsOverlay
• CartoLayer
• DeckLayer/DeckRenderer for ArcGIS

Expected Behavior

get_fill_color to parse other elements when mix of str and int

Steps to Reproduce

# this works
layer = pdk.Layer(
    "ScatterplotLayer",
    UK_ACCIDENTS_DATA,
    get_position=["lng", "lat"],
    auto_highlight=True,
    get_radius=1000,
    get_fill_color=['255', "lng > 0 ? 255 : 88", "lng > 0 ? 255 : 88"],
    pickable=True,
)

# this shows all red
layer = pdk.Layer(
    "ScatterplotLayer",
    UK_ACCIDENTS_DATA,
    get_position=["lng", "lat"],
    auto_highlight=True,
    get_radius=1000,
    get_fill_color=[255, '255', '255'],
    pickable=True,
)

Environment

• Framework version: 0.7.1
• Browser: Chrome
• OS: Win10

Logs

no messages