docstr: Fuses with another Transformer into a TransformerUnion.
docstr_tok: ["Fuses","with","another","Transformer","into","a","TransformerUnion","."]
code: def __radd__(self, other):
      """Fuses with another Transformer into a TransformerUnion."""
      from river import compose
  
      return compose.TransformerUnion(other, self)
  
imports: from __future__ import annotations
  import abc
  import typing
  from river import base
label_desc: Use image node_id 2 for calling the BaseTransformer obj's underlying member method code with example usage: obj.__radd__(other) and returns: compose