public static LinearTransformationBuilder mapping(double x1, double y1) {
    checkArgument(isFinite(x1) && isFinite(y1));
    return new LinearTransformationBuilder(x1, y1);
  }

  /**
   * This is an intermediate stage in the construction process. It is returned by {@link
   * LinearTransformation#mapping}. You almost certainly don't want to keep instances around, but

      this.clazz = checkNotNull(clazz);
    }

    @Override
    public Set<V> get() {
      return EnumSet.noneOf(clazz);
    }
  }

  /**
   * An intermediate stage in a {@link MultimapBuilder} in which the key-value collection map
   * implementation has been specified, but the value collection implementation has not.
   *