docstr: Fuses with another Transformer into a TransformerUnion.
docstr_tok: ["Fuses","with","another","Transformer","into","a","TransformerUnion","."]
code: def __add__(self, other):
      """Fuses with another Transformer into a TransformerUnion."""
      from river import compose
  
      return compose.TransformerUnion(self, other)
  
imports: from __future__ import annotations
  import abc
  import typing
  from river import base
label_desc: Use image node_id 1 for calling the BaseTransformer obj's underlying member method code with example usage: obj.__add__(other) and returns: compose