code: public TableWriteItems withPrimaryKeysToDelete(
              PrimaryKey... primaryKeysToDelete) {
          if (primaryKeysToDelete == null)
              this.primaryKeysToDelete = null;
          else {
              Set<String> pkNameSet = null;
              for (PrimaryKey pk : primaryKeysToDelete) {
                  if (pkNameSet == null)
                      pkNameSet = pk.getComponentNameSet();
                  else {
                      if (!pkNameSet.equals(pk.getComponentNameSet())) {
                          throw new IllegalArgumentException(
                              "primary key attribute names must be consistent for the specified primary keys");
                      }
                  }
              }
              this.primaryKeysToDelete = new ArrayList<PrimaryKey>(
                      Arrays.asList(primaryKeysToDelete));
          }
          return this;
      }
docs: Used to specify multiple primary keys to be deleted from the current
  table. A primary key could consist of either a hash-key or both a
  hash-key and a range-key depending on the schema of the table.