class_docstr: The base class for all transformation objects.
  This class implements a single transformation (history)
  and some various niceties.
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docstr: Apply the transformation to audio and annotations.
  
  The input jam is copied and modified, and returned
  contained in a list.
  
  Parameters
  ----------
  jam : jams.JAMS
      A single jam object to modify
  
  Returns
  -------
  jam_list : list
      A length-1 list containing `jam` after transformation
  
  See also
  --------
  core.load_jam_audio
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code: def _transform(self, jam, state):
      """Apply the transformation to audio and annotations.
  
      The input jam is copied and modified, and returned
      contained in a list.
  
      Parameters
      ----------
      jam : jams.JAMS
          A single jam object to modify
  
      Returns
      -------
      jam_list : list
          A length-1 list containing `jam` after transformation
  
      See also
      --------
      core.load_jam_audio
      """
  
      if not hasattr(jam.sandbox, "muda"):
          raise RuntimeError("No muda state found in jams sandbox.")
  
      # We'll need a working copy of this object for modification purposes
      jam_w = copy.deepcopy(jam)
  
      # Push our reconstructor onto the history stack
      jam_w.sandbox.muda["history"].append(
          {"transformer": self.__serialize__, "state": state}
      )
  
      try:
          self.audio(jam_w.sandbox.muda, state)
      except NotImplementedError:
          pass
  
      try:
          self.metadata(jam_w.file_metadata, state)
      except NotImplementedError:
          pass
  
      # Walk over the list of deformers
      for query, function_name in six.iteritems(self.dispatch):
          function = getattr(self, function_name)
          for matched_annotation in jam_w.search(namespace=query):
              function(matched_annotation, state)
  
      return jam_w
  
imports: import numpy
  import copy
  from collections import OrderedDict
  import itertools
  import six
  import inspect
label_desc: Use image node_id 9 for calling the BaseTransformer obj's underlying member method code with example usage: obj._transform(jam, state) and returns: jam_w