code: def _sequence(self, i):
          
  
          c = next(i)
          if c == '!':
              c = next(i)
          if c in ('^', '-', '['):
              c = next(i)
  
          while c != ']':
              if c == '\\':
                  # Handle escapes
                  subindex = i.index
                  try:
                      self._references(i, True)
                  except PathNameException:
                      raise StopIteration
                  except StopIteration:
                      i.rewind(i.index - subindex)
              elif c == '/':
                  raise StopIteration
              c = next(i)
docs: Handle character group.