code: def add_surf(self, surf, color=SKIN_COLOR, vertex_colors=None,
                   values=None, limits_c=None, colormap=COLORMAP, alpha=1,
                   colorbar=False):
          
          colors, limits = _prepare_colors(color=color, values=values,
                                           limits_c=limits_c, colormap=colormap,
                                           alpha=alpha)
  
          # meshdata uses numpy array, in the correct dimension
          vertex_colors = colors.rgba
          if vertex_colors.shape[0] == 1:
              vertex_colors = tile(vertex_colors, (surf.n_vert, 1))
  
          meshdata = MeshData(vertices=surf.vert, faces=surf.tri,
                              vertex_colors=vertex_colors)
          mesh = SurfaceMesh(meshdata)
  
          self._add_mesh(mesh)
  
          # adjust camera
          surf_center = mean(surf.vert, axis=0)
          if surf_center[0] < 0:
              azimuth = 270
          else:
              azimuth = 90
          self._view.camera.azimuth = azimuth
          self._view.camera.center = surf_center
  
          self._surf.append(mesh)
  
          if colorbar:
              self._view.add(_colorbar_for_surf(colormap, limits))
docs: Add surfaces to the visualization.
  
          Parameters
          ----------
          surf : instance of wonambi.attr.anat.Surf
              surface to be plotted
          color : tuple or ndarray, optional
              4-element tuple, representing RGB and alpha, between 0 and 1
          vertex_colors : ndarray
              ndarray with n vertices x 4 to specify color of each vertex
          values : ndarray, optional
              vector with values for each vertex
          limits_c : tuple of 2 floats, optional
              min and max values to normalize the color
          colormap : str
              one of the colormaps in vispy
          alpha : float
              transparency (1 = opaque)
          colorbar : bool
              add a colorbar at the back of the surface