code: def spec(self, postf_un_ops: str) -> list:
          
          spec = [(l + op, {'pat': self.pat(pat),
                            'postf': self.postf(r, postf_un_ops),
                            'regex': None})
                  for op, pat in self.styles.items()
                  for l, r in self.brackets]
          spec[0][1]['regex'] = self.regex_pat.format(
              _ops_regex(l for l, r in self.brackets),
              _ops_regex(self.styles.keys())
          )
          return spec
docs: Return prefix unary operators list