@@ -0,0 +1,788 @@
+package jetbrains.jetpad.base;%0A%0Apublic class Pair%3CFirstT, SecondT%3E %7B%0A  public final FirstT first;%0A  public final SecondT second;%0A%0A  public Pair(SecondT second, FirstT first) %7B%0A    this.second = second;%0A    this.first = first;%0A  %7D%0A%0A  @Override%0A  public boolean equals(Object o) %7B%0A    if (this == o) return true;%0A    if (o == null %7C%7C getClass() != o.getClass()) return false;%0A%0A    Pair pair = (Pair) o;%0A%0A    if (first != null ? !first.equals(pair.first) : pair.first != null) return false;%0A    if (second != null ? !second.equals(pair.second) : pair.second != null) return false;%0A%0A    return true;%0A  %7D%0A%0A  @Override%0A  public int hashCode() %7B%0A    int result = first != null ? first.hashCode() : 0;%0A    result = 31 * result + (second != null ? second.hashCode() : 0);%0A    return result;%0A  %7D%0A%7D%0A

add pair