code: def engine(self, engine):
      engine = engine.lower()
      if engine not in backend.ENGINES:
          raise ValueError("unknown engine: %r" % engine)
      self._engine = engine
  
imports: import codecs
  import io
  import locale
  import logging
  import os
  from ._compat import text_type
  from .None import backend
  from .None import tools
label_desc: Use image node_id 2 for calling the Base obj's underlying member method code with example usage: obj.engine(engine) without return types