diff --git a/kwant/graph/core.pyx b/kwant/graph/core.pyx index 2ef377be901662cf5afd31b248333757e18dc606..eca0c49d6be073cd7bf64fda75bf4fb6302c94bf 100644 --- a/kwant/graph/core.pyx +++ b/kwant/graph/core.pyx @@ -72,7 +72,7 @@ cdef class Graph: raise MemoryError self.capacity = capacity - cpdef gint add_edge(self, gint tail, gint head): + cpdef gint add_edge(self, gint tail, gint head) except -1: """Add the directed edge (`tail`, `head`) to the graph. Parameters