code: def get_alldictkeys(ddict, parent=None):
      
      parent = [] if parent is None else parent
  
      if not isinstance(ddict, dict):
          return [tuple(parent)]
      return reduce(
          list.__add__,
          [get_alldictkeys(v, parent + [k]) for k, v in ddict.items()],
          [])
docs: Get all keys in a dict