OEReceptorSetBoundLigand
OEReceptorSetBoundLigand(rec: Union[OEGraphMol,OEMol,OEQMol],
boundLig: Union[OEGraphMol,OEMol,OEQMol]) -> bool
Sets the bound ligand on receptor to be a copy of boundLigand.
Returns true if successful.
It is only valid to call this function if receptor is a valid receptor
(i.e., OEIsReceptor returns true).