code: def normal(self, t, i):
          
  
          current = []
  
          if t == "\\":
              try:
                  t = next(i)
                  current.extend(self.reference(t, i))
              except StopIteration:
                  current.append(t)
          elif t == "(":
              current.extend(self.subgroup(t, i))
          elif self.verbose and t == "#":
              current.extend(self.verbose_comment(t, i))
          elif t == "[":
              current.extend(self.char_groups(t, i))
          else:
              current.append(t)
          return current
docs: Handle normal chars.