code: def salt_master(project, target, module, args=None, kwargs=None):
      
      client = project.cluster.head.ssh_client
  
      cmd = ['salt']
      cmd.extend(generate_salt_cmd(target, module, args, kwargs))
      cmd.append('--timeout=300')
      cmd.append('--state-output=mixed')
      cmd = ' '.join(cmd)
  
      output = client.exec_command(cmd, sudo=True)
      if output['exit_code'] == 0:
          return output['stdout']
      else:
          return output['stderr']
docs: Execute a `salt` command in the head node