docstr: Creates a Grouper.
docstr_tok: ["Creates","a","Grouper","."]
code: def __rmul__(self, other):
      """Creates a Grouper."""
      return self * other
  
imports: from __future__ import annotations
  import abc
  import typing
  from river import base
label_desc: Use image node_id 4 for calling the BaseTransformer obj's underlying member method code with example usage: obj.__rmul__(other) and returns: unknown