import org.jspecify.annotations.Nullable;

/**
 * This class provides a skeletal implementation of {@link Network}. It is recommended to extend
 * this class rather than implement {@link Network} directly.
 *
 * <p>The methods implemented in this class should not be overridden unless the subclass admits a
 * more efficient implementation.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 * @param <E> Edge parameter type

 * to implement the related methods as well. Finally, two collection views are provided: {@link
 * #elementSet} contains the distinct elements of the multiset "with duplicates collapsed", and
 * {@link #entrySet} is similar but contains {@link Entry Multiset.Entry} instances, each providing
 * both a distinct element and the count of that element.
 *
 * <p>In addition to these required methods, implementations of {@code Multiset} are expected to

   *
   * <p><b>Java 11+ users:</b> use {@link Writer#nullWriter()} instead. Note that the {@link
   * CharStreams} method returns a singleton writer whose {@code close} method has no effect, while
   * the {@link Writer#nullWriter()} method returns a new instance whose methods throw after the
   * instance is {@link Writer#close() closed}.
   *
   * @since 15.0
   */
  public static Writer nullWriter() {

  }

  /**
   * Builds an instance for datasets which contains {@link Double#NaN}. The {@link #isHorizontal}
   * and {@link #isVertical} methods return {@code false} and the {@link #slope}, and {@link
   * #transform} methods all return {@link Double#NaN}. The {@link #inverse} method returns the same
   * instance.
   */
  public static LinearTransformation forNaN() {
    return NaNLinearTransformation.INSTANCE;
  }

  /**
   * Tries to perform a "full" garbage collection cycle (including processing of weak references and
   * invocation of finalize methods) and waits for it to complete. Ensures that at least one weak
   * reference has been cleared and one {@code finalize} method has been run before this method
   * returns. This method may be useful when testing the garbage collection mechanism itself, or
   * inhibiting a spontaneous GC initiation in subsequent code.

    // -----------/
    // - Methods -/
    // -----------/

    /**
     * Method setFileComment.
     *
     * @param fileComment a fileComment object.
     */
    public void setFileComment(String fileComment) {
        this.fileComment = fileComment;
    } // -- void setFileComment( String )

    /**
     * Method write.
     *
     * @param writer a writer object.

 *
 * <p>
 * Reports simple superclass changes (e.g. the removal of a superclass) as a breaking change, as it affects what methods can be
 * called with the given type, even if the methods and fields inherited don't change.
 * </p>
 */
class BinaryBreakingSuperclassChangeRule extends AbstractSuperClassChangesRule {

 * callers. Instead, accept {@link Iterable} and have your method or constructor body pass it to the
 * appropriate {@code copyOf} method itself.
 *
 * <p>Expressing the immutability guarantee directly in the type that user code references is a
 * powerful advantage. Although Java offers certain immutable collection factory methods, such as
 * {@link Collections#singleton(Object)} and <a

   * methods ensure that the {@code WrappedCollection} and map remain consistent.
   *
   * <p>A subcollection, such as a sublist, contains some of the values for a given key. Its
   * ancestor field points to the full wrapped collection with all values for the key. The
   * subcollection {@code refreshIfEmpty}, {@code removeIfEmpty}, and {@code addToMap} methods call

import java.util.Collection;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
import org.junit.Ignore;

/**
 * Tester for the {@code size} methods of {@code Multimap} and its views.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")