code: def addthisbunch(bunchdt, data, commdct, thisbunch, theidf):
      
      key = thisbunch.key.upper()
      obj = copy.copy(thisbunch.obj)
      abunch = obj2bunch(data, commdct, obj)
      bunchdt[key].append(abunch)
      return abunch
docs: add a bunch to model.
      abunch usually comes from another idf file
      or it can be used to copy within the idf file