code: public DescribeFileSystemsResult withFileSystems(FileSystem... fileSystems) {
          if (this.fileSystems == null) {
              setFileSystems(new java.util.ArrayList<FileSystem>(fileSystems.length));
          }
          for (FileSystem ele : fileSystems) {
              this.fileSystems.add(ele);
          }
          return this;
      }
docs: <p>
  An array of file system descriptions.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setFileSystems(java.util.Collection)} or {@link #withFileSystems(java.util.Collection)} if you want to
  override the existing values.
  </p>
  
  @param fileSystems
  An array of file system descriptions.
  @return Returns a reference to this object so that method calls can be chained together.