code: def list_argmaxima(list_):
      r
      argmax = list_argmax(list_)
      maxval = list_[argmax]
      argmaxima = np.where((np.isclose(maxval, list_)))[0]
      return argmaxima
docs: r"""
      Args:
          list_ (list):
  
      Returns:
          list: argmaxima
  
      CommandLine:
          python -m utool.util_list --exec-list_argmaxima
  
      Example:
          >>> # ENABLE_DOCTEST
          >>> from utool.util_list import *  # NOQA
          >>> list_ = np.array([1, 2, 3, 3, 3, 2, 1])
          >>> argmaxima = list_argmaxima(list_)
          >>> result = ('argmaxima = %s' % (str(argmaxima),))
          >>> print(result)
          argmaxima = [2 3 4]