import com.google.common.collect.Iterators;
import com.google.common.collect.Sets;
import com.google.common.collect.UnmodifiableIterator;
import com.google.common.math.IntMath;
import com.google.common.primitives.Ints;
import java.util.AbstractSet;
import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * This class provides a skeletal implementation of {@link BaseGraph}.
 *