class_docstr: Builds Approximation instance from a given trace,
  it has the same interface as variational approximation
class_docstr_tok: ["Builds","Approximation","instance","from","a","given","trace",",","it","has","the","same","interface","as","variational","approximation"]
code: def __str__(self):
      if isinstance(self.histogram, pytensor.compile.SharedVariable):
          shp = ", ".join(map(str, self.histogram.shape.eval()))
      else:
          shp = "None, " + str(self.ddim)
      return f"{self.__class__.__name__}[{shp}]"
  
imports: from typing import Optional
  import numpy
  import pytensor
  from arviz import InferenceData
  from pytensor import tensor
  from pytensor.graph.basic import Variable
  from pytensor.graph.replace import graph_replace
  from pytensor.tensor.variable import TensorVariable
  import pymc
  from pymc.blocking import DictToArrayBijection
  from pymc.distributions.dist_math import rho2sigma
  from pymc.util import makeiter
  from pymc.variational import opvi
  from pymc.variational.opvi import Approximation, Group, NotImplementedInference, _known_scan_ignored_inputs, node_property
label_desc: Use image node_id 11 for calling the EmpiricalGroup obj's underlying member method code with example usage: obj.__str__() and returns: self, str, shp, str