var keys []string
	keyval := make(map[string]string, len(headers))
	for key := range headers {
		lkey := strings.ToLower(key)
		if !strings.HasPrefix(lkey, "x-amz-") {
			continue
		}
		keys = append(keys, lkey)
		keyval[lkey] = strings.Join(headers[key], ",")
	}
	sort.Strings(keys)
	var canonicalHeaders []string
	for _, key := range keys {

  private static final Predicate<@Nullable Integer> EVEN = input -> input == null || input % 2 == 0;
  static final Predicate<Entry<String, Integer>> CORRECT_LENGTH =
      input -> input.getKey().length() == input.getValue();

  abstract Map<String, Integer> createUnfiltered();

  public void testFilteredKeysIllegalPut() {
    Map<String, Integer> unfiltered = createUnfiltered();

                    Map<String, String> map = CompactLinkedHashMap.create();
                    for (Entry<String, String> entry : entries) {
                      map.put(entry.getKey(), entry.getValue());
                    }
                    return map;
                  }
                })
            .named("CompactLinkedHashMap")
            .withFeatures(

        return attrib;
    }

    @Override
    public int getLength() {
        return 1;
    }

    @Override
    public QName getName() {
        return new QName(null, attrib.getKey());
    }

    @Override
    public boolean isActual() {
        return true;
    }

    @Override
    public boolean isCollection() {
        return false;
    }

    @Override

        if (metadataMap == null) {
            metadataMap = new HashMap<>();
        }

        ArtifactMetadata m = metadataMap.get(metadata.getKey());
        if (m != null) {
            m.merge(metadata);
        } else {
            metadataMap.put(metadata.getKey(), metadata);
        }
    }

    @Override
    public Collection<ArtifactMetadata> getMetadataList() {
        if (metadataMap == null) {

        if (from != null) {
            for (Map.Entry<K, ? extends Artifact> entry : from.entrySet()) {
                to.put(entry.getKey(), ArtifactUtils.copyArtifact(entry.getValue()));
            }
        }

        return to;
    }

    private static <T> List<T> copyList(List<T> original) {
        List<T> copy = null;

                            .entrySet()
                            .stream()
                            .filter(p -> p.getValue() > 1)
                            .map(Map.Entry::getKey)
                            .collect(Collectors.toSet());
                }
            }
        }
        return duplicateIds;
    }

    public List<BuildStep> sortedNodes() {

    return new AbstractMapEntry<K, V2>() {
      @Override
      @ParametricNullness
      public K getKey() {
        return entry.getKey();
      }

      @Override
      @ParametricNullness
      public V2 getValue() {
        return transformer.transformEntry(entry.getKey(), entry.getValue());
      }
    };
  }

    return new AbstractMapEntry<K, V2>() {
      @Override
      @ParametricNullness
      public K getKey() {
        return entry.getKey();
      }

      @Override
      @ParametricNullness
      public V2 getValue() {
        return transformer.transformEntry(entry.getKey(), entry.getValue());
      }
    };
  }

      @Override
      protected @Nullable E computeNext() {
        while (entries.hasNext()) {
          Entry<E, ?> entry = entries.next();
          if (targetNode.equals(entry.getValue())) {
            return entry.getKey();
          }
        }
        return endOfData();
      }
    };
  }

  @Override
  public boolean contains(@Nullable Object edge) {
    return targetNode.equals(outEdgeToNode.get(edge));
  }