code: public @NotNull ListAssert contains(@Nullable Object o, @NotNull Index index) {
      checkNotNull(index);
      isNotNull().isNotEmpty();
      int indexValue = index.value();
      int listSize = actualGroupSize();
      if (indexValue < 0 || indexValue >= listSize) {
        failIndexOutOfBounds(indexValue);
      }
      Object actualElement = actual.get(indexValue);
      if (!areEqual(actualElement, o)) {
        failElementNotFound(o, actualElement, indexValue);
      }
      return this;
    }
docs: Verifies that the actual {@code List} contains the given object at the given index.
  
  @param o     the object to look for.
  @param index the index where the object should be stored in the actual {@code List}.
  @return this assertion object.
  @throws NullPointerException      if the given {@code Index} is {@code null}.
  @throws IndexOutOfBoundsException if the value of the given {@code Index} is negative, or equal to or greater than
  the size of the actual {@code List}.
  @throws AssertionError            if the given {@code List} does not contain the given object at the given index.