docs: def cleanDir(self):
          ''' Remove existing json datafiles in the target directory. '''
          if os.path.isdir(self.outdir):
              baddies = ['tout.json','nout.json','hout.json']
              for file in baddies:
                  filepath = os.path.join(self.outdir,file)
                  if os.path.isfile(filepath):
                      os.remove(filepath)