docstr: Should be subclassed to check if the source and target plots
  are compatible to perform the linking.
docstr_tok: ["Should","be","subclassed","to","check","if","the","source","and","target","plots","are","compatible","to","perform","the","linking","."]
code: def validate(self):
      """
      Should be subclassed to check if the source and target plots
      are compatible to perform the linking.
      """
  
imports: import numpy
  from bokeh.models import CustomJS, Toolbar
  from bokeh.models.tools import RangeTool
  from ...core.util import isscalar
  from ..links import DataLink, Link, RangeToolLink, RectanglesTableLink, SelectionLink, VertexTableLink
  from ..plot import GenericElementPlot, GenericOverlayPlot
label_desc: Use image node_id 4 for calling the LinkCallback obj's underlying member method code with example usage: obj.validate() without return types