class_docstr: Abstract base class for time stretching
  
  This contains the deformation functions and
  annotation query mapping, but does not manage
  state or parameters.
code: def metadata(metadata, state):
      # Deform the metadata
      metadata.duration /= state["rate"]
  
imports: import pyrubberband
  import numpy
  from ..base import BaseTransformer, _get_rng
label_desc: Use image node_id 3 for calling the AbstractTimeStretch obj's underlying member method code with example usage: obj.metadata(metadata, state) without return types