docs: def remove_option_regexp(self, section, option, expr):
          '''
          Remove an option with a value matching the expression. Works on single
          values and multivars.
          '''
          if not section or section == self.DEFAULTSECT:
              sectdict = self._defaults
          else:
              try:
                  sectdict = self._sections[section]
              except KeyError:
                  raise NoSectionError(  # pylint: disable=undefined-variable
                      salt.utils.stringutils.to_str(section))
          option = self.optionxform(option)
          if option not in sectdict:
              return False
          regexp = re.compile(expr)
          if isinstance(sectdict[option], list):
              new_list = [x for x in sectdict[option] if not regexp.search(x)]
              # Revert back to a list if we removed all but one item
              if len(new_list) == 1:
                  new_list = new_list[0]
              existed = new_list != sectdict[option]
              if existed:
                  del sectdict[option]
                  sectdict[option] = new_list
              del new_list
          else:
              existed = bool(regexp.search(sectdict[option]))
              if existed:
                  del sectdict[option]
          return existed