docs: def _low_level_exec_command(self, conn, cmd, tmp, sudoable=False, executable=None):
          ''' execute a command string over SSH, return the output '''
  
          if executable is None:
              executable = '/bin/sh'
  
          sudo_user = self.sudo_user
          rc, stdin, stdout, stderr = conn.exec_command(cmd, tmp, sudo_user, sudoable=sudoable, executable=executable)
  
          if type(stdout) not in [ str, unicode ]:
              out = ''.join(stdout.readlines())
          else:
              out = stdout
  
          if type(stderr) not in [ str, unicode ]:
              err = ''.join(stderr.readlines())
          else:
              err = stderr
  
          if rc != None:
              return dict(rc=rc, stdout=out, stderr=err )
          else:
              return dict(stdout=out, stderr=err )