Thank you very much, @i_mazlov! This is what I needed!

Hello everyone!
I'm trying to add knots to the c4d.Gradient object, in GvNode. But the changes are not applied to the parameter, maybe I missed something, and this parameter needs to be updated?

import c4d
import redshift

knots = [
    (c4d.Vector(1,0,1), 0.25, 0.25, 0.25),
    (c4d.Vector(0,1,1), 0.5, 0.5, 0.5),
    (c4d.Vector(1,1,0), 0.75, 0.75, 0.75),
    
]

def main() -> None:
    rs_material = doc.GetActiveMaterial()
    if not rs_material.GetTypeName() == "RS Shader Graph":
        print(rs_material.GetTypeName())
        return
    
    # Get node master and root
    nm = redshift.GetRSMaterialNodeMaster(rs_material)
    root = nm.GetRoot()
    
    # Create RSRamp gvNode
    ramp_node = nm.CreateNode(root, 1036227)
    ramp_node[c4d.GV_REDSHIFT_SHADER_META_CLASSNAME] = 'RSRamp'
    
    # Get Gradient
    gradient = ramp_node[c4d.REDSHIFT_SHADER_RSRAMP_RAMP]
    gradient.FlushKnots()
    for i, knot in enumerate(knots):
        gradient.InsertKnot(knot[0], knot[1], knot[2], knot[3], i )
    
    #  Check values
    for i in range(gradient.GetKnotCount()):
        knot = gradient.GetKnot(i)
        col = knot.get("col")
        pos = knot.get("pos")
        br = knot.get('brightness')
        print(f"col = {col}, pos = {pos}, brightness = {br} ")

main()