TranslationalSymmetry does not work with my SimpleSite Family. Therefore, I attach the leads manually. I Use class kwant.builder.BuilderLead(builder, interface).

I define a builder in the following way:

#The tight-binding system of a left lead.
left_lead = kwant.Builder()

#Add sites lead
left_lead[lat(x1, y1)] = 1.5
left_lead[lat(x2, y2)] = 1.5
etc

#Add hoppings
left_lead[lat(x2, y2), lat(x1, y1)] = 2j
etc

The same way I define the interface(wich called left_sequence) but without the hoppings.

l_lead = kwant.builder.BuilderLead(left_lead, left_sequence).

But it does not work. Where I'm wrong?

As the lead I want to use the left and right boundary of my graphene atoms.