A fragment of my protein is predicted by I-TASSER to be similar to a homodimer module. But the predicted pdb file (named copy) is only a monomer. Can I generate a dimer using pymol? I tried symexp sym, copy, copy, 2.5, which would work for other known pdb file,  but got the error message "no symmetry loaded". Can anyone tell me how to create a dimer from my predcited monomer? Thanks,