code: def get_items_by_group(self, group, case_sensitive = True):
          
          result = []
          if not group:
              for item in self._items:
                  if not item.groups:
                      result.append(item)
              return result
          if not case_sensitive:
              group = group.lower()
          for item in self._items:
              if group in item.groups:
                  result.append(item)
              elif not case_sensitive and group in [g.lower() for g
                                                              in item.groups]:
                  result.append(item)
          return result
docs: Return a list of items within a given group.
  
          :Parameters:
              - `name`: name to look-up
              - `case_sensitive`: if `False` the matching will be case
                insensitive.
          :Types:
              - `name`: `unicode`
              - `case_sensitive`: `bool`
  
          :Returntype: `list` of `RosterItem`