docs: def gemset_list(ruby='default', runas=None):
      '''
      List all gemsets for the given ruby.
  
      ruby : default
          The ruby version for which to list the gemsets
  
      runas
          The user under which to run rvm. If not specified, then rvm will be run
          as the user under which Salt is running.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' rvm.gemset_list
      '''
      gemsets = []
      output = _rvm_do(ruby, ['rvm', 'gemset', 'list'], runas=runas)
      if output:
          regex = re.compile('^   ([^ ]+)')
          for line in output.splitlines():
              match = regex.match(line)
              if match:
                  gemsets.append(match.group(1))
      return gemsets