code: def fill_in_datakeys(example_parameters, dexdata):
      
      # default initialization of 'datakey' key with entries from data dictionary
      for exkey in example_parameters:
          if 'datakey' not in example_parameters[exkey]:
              if exkey in dexdata:
                  example_parameters[exkey]['datakey'] = exkey
              else:
                  example_parameters[exkey]['datakey'] = 'unspecified in dexdata'
      return example_parameters
docs: Update the 'examples dictionary' _examples.example_parameters.
  
      If a datakey (key in 'datafile dictionary') is not present in the 'examples
      dictionary' it is used to initialize an entry with that key.
  
      If not specified otherwise, any 'exkey' (key in 'examples dictionary') is
      used as 'datakey'.