float  agentchannelvalues(<geometry>geometry, int prim)
If only a single channel value is needed, using agentchannelvalue instead can be significantly faster.
Returns an empty array if
prim is out of range or is not an agent primitive.
The name of the geometry file to reference. Inside Houdini, this may be
op:full_path_to_sop to reference a SOP.
The number of the input to reference. The first input is number
0, the second is
The primitive number.