class_docstr: Creates a "future" reference to a value within a top-level or a nested
  dictionary.  See also class DeferredDictLookup.
class_docstr_tok: ["Creates","a","``","future","''","reference","to","a","value","within","a","top-level","or","a","nested","dictionary",".","See","also","class","DeferredDictLookup","."]
docstr: This method overrides ValueGetterBase's "pure virtual" method.  It
  returns the referenced value.  The derived class is NOT responsible for
  fully resolving the reference'd value in the event the value resolves to
  another ValueGetterBase-based instance -- this is handled automatically
  within ValueGetterBase implementation.
  
  topContainer: The top-level container (dict, tuple, or list [sub-]instance)
                within whose context the value-getter is applied.  If
                self.__referenceDict is None, then topContainer will be used
                as the reference dictionary for resolving our dictionary key
                chain.
  
  Returns:      The value referenced by this instance (which may be another
                value-getter instance)
docstr_tok: ["This","method","overrides","ValueGetterBase","'s","``","pure","virtual","''","method",".","It","returns","the","referenced","value",".","The","derived","class","is","NOT","responsible","for","fully","resolving","the","reference","'d","value","in","the","event","the","value","resolves","to","another","ValueGetterBase-based","instance","--","this","is","handled","automatically","within","ValueGetterBase","implementation",".","topContainer",":","The","top-level","container","(","dict",",","tuple",",","or","list","[","sub-","]","instance",")","within","whose","context","the","value-getter","is","applied",".","If","self.__referenceDict","is","None",",","then","topContainer","will","be","used","as","the","reference","dictionary","for","resolving","our","dictionary","key","chain",".","Returns",":","The","value","referenced","by","this","instance","(","which","may","be","another","value-getter","instance",")"]
code: def handleGetValue(self, topContainer):
      """This method overrides ValueGetterBase's "pure virtual" method.  It
      returns the referenced value.  The derived class is NOT responsible for
      fully resolving the reference'd value in the event the value resolves to
      another ValueGetterBase-based instance -- this is handled automatically
      within ValueGetterBase implementation.
  
      topContainer: The top-level container (dict, tuple, or list [sub-]instance)
                    within whose context the value-getter is applied.  If
                    self.__referenceDict is None, then topContainer will be used
                    as the reference dictionary for resolving our dictionary key
                    chain.
  
      Returns:      The value referenced by this instance (which may be another
                    value-getter instance)
      """
      value = (
          self.__referenceDict
          if self.__referenceDict is not None
          else topContainer
      )
      for key in self.__dictKeyChain:
          value = value[key]
  
      return value
  
file_path: nupic-legacy/src/nupic/frameworks/opf/exp_description_helpers.py
imports: import os
  import imp
  from nupic.data.dict_utils import rUpdate
label_desc: Use image node_id 2 for calling the DictValueGetter obj's underlying member method code with example usage: obj.handleGetValue(topContainer) and returns: value