Use this if you are using igraph from R
| simplified {igraph} | R Documentation | 
Constructor modifier to drop multiple and loop edges
simplified()
Other constructor modifiers: 
with_edge_(),
with_graph_(),
with_vertex_(),
without_attr(),
without_loops(),
without_multiples()
sample_(pa(10, m = 3, algorithm = "bag"))
sample_(pa(10, m = 3, algorithm = "bag"), simplified())