docs: def _split_op(
              self, identifier, hs_label=None, dagger=False, args=None):
          """Return `name`, total `subscript`, total `superscript` and
          `arguments` str. All of the returned strings are fully rendered.
  
          Args:
              identifier (str or SymbolicLabelBase): A (non-rendered/ascii)
                  identifier that may include a subscript. The output `name` will
                  be the `identifier` without any subscript
              hs_label (str): The rendered label for the Hilbert space of the
                  operator, or None. Returned unchanged.
              dagger (bool): Flag to indicate whether the operator is daggered.
                  If True, :attr:`dagger_sym` will be included in the
                  `superscript` (or  `subscript`, depending on the settings)
              args (list or None): List of arguments (expressions). Each element
                  will be rendered with :meth:`doprint`. The total list of args
                  will then be joined with commas, enclosed
                  with :attr:`_parenth_left` and :attr:`parenth_right`, and
                  returnd as the `arguments` string
          """
          if self._isinstance(identifier, 'SymbolicLabelBase'):
              identifier = QnetAsciiDefaultPrinter()._print_SCALAR_TYPES(
                  identifier.expr)
          name, total_subscript = self._split_identifier(identifier)
          total_superscript = ''
          if (hs_label not in [None, '']):
              if self._settings['show_hs_label'] == 'subscript':
                  if len(total_subscript) == 0:
                      total_subscript = '(' + hs_label + ')'
                  else:
                      total_subscript += ',(' + hs_label + ')'
              else:
                  total_superscript += '(' + hs_label + ')'
          if dagger:
              total_superscript += self._dagger_sym
          args_str = ''
          if (args is not None) and (len(args) > 0):
              args_str = (self._parenth_left +
                          ",".join([self.doprint(arg) for arg in args]) +
                          self._parenth_right)
          return name, total_subscript, total_superscript, args_str