new_contents: """
  useful for debugging ucscsession.tracks.Track
  """
  import webbrowser
  import ucscsession
  import ucscsession.tracks
  import pybedtools
  from bs4 import BeautifulSoup
  
  reload(ucscsession)
  reload(ucscsession.tracks)
  
  u = ucscsession.UCSCSession()
  response = u.session.get(u.tracks_url)
  b = BeautifulSoup(response.text)
  
  cells = b('td')
  
  # Adjust `start` to skip <td>s with problems
  start = 50
  for i in range(start, len(cells)):
      try:
          ucscsession.tracks.Track(cells[i], u)
      except ucscsession.tracks.TrackException as e:
          print e.message
  
subject: add track_debug.py