code: def check_commands(self, cmd_list):
          
          # if a string is passed then convert it to a list.  This prevents an
          # easy mistake that could be made
          if isinstance(cmd_list, basestring):
              cmd_list = [cmd_list]
  
          for cmd in cmd_list:
              if self.command_run("which {}".format(cmd)) == 0:
                  return cmd
docs: Checks to see if commands in list are available using ``which``.
  
          returns the first available command.
  
          If a string is passed then that command will be checked for.