old_contents: #!/usr/bin/env python
  
  import six
  import numpy as np
  import pandas as pd
  
  
  class TimeSlice(object):
      """
      A slice of time:  has a start time, a duration, and a reference to an Audio object.
      """
  
      def __init__(self, time, duration, audio, unit='s'):
          self.time = pd.to_timedelta(time, unit=unit)
          self.duration = pd.to_timedelta(duration, unit=unit)
          self.audio = audio
  
      def __repr__(self):
      	args = self.time, self.duration
      	return '<TimeSlice, start:{0:.2f}, duration:{1:.2f}'.format(*args)
  
  class TimingList(list):
      """
      A list of TimeSlices.  
      """
  
      def __init__(self, name, timings, audio, unit='s'):
          # This assumes that we're going to get a list of tuples (start, duration) from librosa,
          # which may or may not be true.
          self.name = name
          for (start, duration) in timings:
              slice = TimeSlice(start, duration, audio, unit=unit)
              self.append(slice)
  
new_contents: #!/usr/bin/env python
  
  import six
  import numpy as np
  import pandas as pd
  
  
  class TimeSlice(object):
      """
      A slice of time:  has a start time, a duration, and a reference to an Audio object.
      """
  
      def __init__(self, time, duration, audio, unit='s'):
          self.time = pd.to_timedelta(time, unit=unit)
          self.duration = pd.to_timedelta(duration, unit=unit)
          self.audio = audio
  
      def __repr__(self):
          args = self.time.delta / 1000000000.0, self.duration.delta / 1000000000.0
          return '<TimeSlice, start: {0:.2f}, duration: {1:.2f}'.format(*args)
  
  class TimingList(list):
      """
      A list of TimeSlices.  
      """
  
      def __init__(self, name, timings, audio, unit='s'):
          # This assumes that we're going to get a list of tuples (start, duration) from librosa,
          # which may or may not be true.
          self.name = name
          for (start, duration) in timings:
              slice = TimeSlice(start, duration, audio, unit=unit)
              self.append(slice)
  
subject: Fix formatting bug in repr