e'</span>,J5,<span class="string">'label'</span>,<span class="string">'J5'</span>,<span class="string">'color'</span>,<span class="string">'purple'</span>)

banb.addcoupling(<span class="string">'mat'</span>,<span class="string">'J1'</span>,<span class="string">'bond'</span>,1)
banb.addcoupling(<span class="string">'mat'</span>,<span class="string">'J2'</span>,<span class="string">'bond'</span>,3)
banb.addcoupling(<span class="string">'mat'</span>,<span class="string">'J4'</span>,<span class="string">'bond'