code: func (f *Fpdf) TransformSkewY(angleY, x, y float64) {
  	f.TransformSkew(0, angleY, x, y)
  }
docs: // TransformSkewY vertically skews the following text, drawings and images
  // keeping the point (x, y) stationary. angleY ranges from -90 degrees (skew to
  // the bottom) to 90 degrees (skew to the top).
  //
  // The TransformBegin() example demonstrates this method.