class_docstr: Stores a polyphonic sequence as a stream of single-note events.
  
  Events are PolyphonicEvent tuples that encode event type and pitch.
class_docstr_tok: ["Stores","a","polyphonic","sequence","as","a","stream","of","single-note","events",".","Events","are","PolyphonicEvent","tuples","that","encode","event","type","and","pitch","."]
docstr: Adds steps of silence to the end of the sequence.
docstr_tok: ["Adds","steps","of","silence","to","the","end","of","the","sequence","."]
code: def _append_silence_steps(self, num_steps):
      """Adds steps of silence to the end of the sequence."""
      for _ in range(num_steps):
          self._events.append(
              PolyphonicEvent(
                  event_type=PolyphonicEvent.STEP_END, pitch=None
              )
          )
  
imports: from __future__ import division
  import collections
  import copy
  from magenta.pipelines import statistics
  from note_seq import constants
  from note_seq import events_lib
  from note_seq import sequences_lib
  from note_seq.protobuf import music_pb2
  from six.moves import range
  import tensorflow.compat.v1
label_desc: Use image node_id 5 for calling the PolyphonicSequence obj's underlying member method code with example usage: obj._append_silence_steps(num_steps) without return types