code: def append_surface(self, name, surface, alpha=1.):
          '''
          Append Cairo surface as new layer on top of existing layers.
  
          Args
          ----
  
              name (str) : Name of layer.
              surface (cairo.ImageSurface) : Surface to render.
              alpha (float) : Alpha/transparency level in the range `[0, 1]`.
          '''
          self.insert_surface(position=self.df_surfaces.index.shape[0],
                              name=name, surface=surface, alpha=alphaf append_surface(self, name, surface, alpha=1.):
          '''
          Append Cairo surface as new layer on top of existing layers.
  
          Args
          ----
  
              name (str) : Name of layer.
              surface (cairo.ImageSurface) : Surface to render.
              alpha (float) : Alpha/transparency level in the range `[0, 1]`.
          '''
          self.insert_surface(position=self.df_surfaces.index.shape[0],
                              name=name, surface=surface, alpha=alpha)
docs: Append Cairo surface as new layer on top of existing layers.
  
          Args
          ----
  
              name (str) : Name of layer.
              surface (cairo.ImageSurface) : Surface to render.
              alpha (float) : Alpha/transparency level in the range `[0, 1]`.