old_contents: from __future__ import absolute_import
  
  from .parsed_params import param_defs, TRACKTYPES
  
  # http://genome-source.cse.ucsc.edu/gitweb/
  #       ?p=kent.git;a=blob;f=src/hg/makeDb/trackDb/README;hb=HEAD
  
  param_dict = {i.name: i for i in param_defs}
  
  # These should at least be first...
  initial_params = ['track', 'bigDataUrl', 'shortLabel', 'longLabel', 'type']
  
  track_fields = {i: initial_params[:] for i in TRACKTYPES}
  
  observed_types = set()
  for param in param_defs:
      observed_types.update(param.types)
  
  for tracktype in observed_types:
      lst = track_fields[tracktype]
      for param in param_defs:
          if tracktype in param.types:
              lst.append(param.name)
  
  INDENT = '    '
  
new_contents: from __future__ import absolute_import
  
  from .parsed_params import param_defs, TRACKTYPES
  
  # http://genome-source.cse.ucsc.edu/gitweb/
  #       ?p=kent.git;a=blob;f=src/hg/makeDb/trackDb/README;hb=HEAD
  
  param_dict = {i.name: i for i in param_defs}
  
  # These should at least be first...
  initial_params = ['track', 'bigDataUrl', 'shortLabel', 'longLabel', 'type']
  trackhub_specific = ["source", "tracktype", "name"]
  
  
  track_fields = {i: initial_params[:] for i in TRACKTYPES}
  
  observed_types = set()
  for param in param_defs:
      observed_types.update(param.types)
  
  for tracktype in observed_types:
      lst = track_fields[tracktype]
      for param in param_defs:
          if tracktype in param.types:
              lst.append(param.name)
  
  INDENT = '    '
  
subject: add missing constants.trackhub_specific list