class_docstr: Mixin class for Cartesian 2D elements to add basic support for
  SelectionExpr streams.
class_docstr_tok: ["Mixin","class","for","Cartesian","2D","elements","to","add","basic","support","for","SelectionExpr","streams","."]
code: def _get_selection_dims(self):
      from .graphs import Graph
  
      if isinstance(self, Graph):
          xdim, ydim = self.nodes.dimensions()[:2]
      else:
          xdim, ydim = self.dimensions()[:2]
  
      invert_axes = self.opts.get("plot").kwargs.get(
          "invert_axes", False
      )
      if invert_axes:
          xdim, ydim = ydim, xdim
      return (xdim, ydim)
  
imports: import sys
  import numpy
  import pandas
  from ..core import Dataset, NdOverlay, util
  from ..streams import Lasso, Selection1D, SelectionXY
  from ..util.transform import dim
  from .annotation import HSpan, VSpan
label_desc: Use image node_id 6 for calling the Selection2DExpr obj's underlying member method code with example usage: obj._get_selection_dims() and returns: xdim,  ydim