code: def arg_to_dict(arg):
      
      if arg is None:
          arg = []
      try:
          arg = dict(arg)
      except ValueError:
          arg = dict.fromkeys(list(arg), {})
  
      return arg
docs: Convert an argument that can be None, list/tuple or dict to dict
  
      Example::
  
          >>> arg_to_dict(None)
          []
          >>> arg_to_dict(['a', 'b'])
          {'a':{},'b':{}}
          >>> arg_to_dict({'a':{'only': 'id'}, 'b':{'only': 'id'}})
          {'a':{'only':'id'},'b':{'only':'id'}}
  
      :return: dict with keys and dict arguments as value