code: public boolean setPartitions(Collection<Collection<Node>> parts) {
          if (!isDisjoint(parts)) {
              return false;
          }
          partitions = parts;
          return true;
      }
docs: Set the node partitions
  
  @param parts disjoint set of nodes
  @return {@code true} iff the partitions have been set. {@code false} if the
  sets were not disjoint