class_docstr: Subclass of the CT2DInterpolator with optional `values`.
  
  This is mainly a demo of the functionality. See
  https://github.com/scipy/scipy/pull/18376 for discussion
class_docstr_tok: ["Subclass","of","the","CT2DInterpolator","with","optional","`","values","`",".","This","is","mainly","a","demo","of","the","functionality",".","See","https",":","\/\/github.com\/scipy\/scipy\/pull\/18376","for","discussion"]
code: def _preprocess_xi(self, *args):
      if self.xi is None:
          (
              self.xi,
              self.interpolation_points_shape,
          ) = interpolate.CloughTocher2DInterpolator._preprocess_xi(
              self, *args
          )
      return self.xi, self.interpolation_points_shape
  
imports: import numpy
  from .common import run_monitored, set_mem_rlimit, Benchmark, safe_import
label_desc: Use image node_id 2 for calling the CloughTocherInterpolatorValues obj's underlying member method code with example usage: obj._preprocess_xi() and returns: self,  self