old_contents: # our constants.
  
  import os
  
  local_path = os.path.dirname(__file__)
  
  xml_doc = os.path.abspath(os.path.join(local_path, 'data', 'fagatelebay_zone.xml'))
  csv_doc = os.path.abspath(os.path.join(local_path, 'data', 'fagatelebay_zone.csv'))
  bathy_raster = os.path.abspath(os.path.join(local_path, 'data', 'bathy5m_clip.tif'))
  
  tbx_file = os.path.abspath(os.path.join(local_path, '..', 'Install', 'toolbox', 'btm_model.tbx'))
  
new_contents: # our constants.
  
  import os
  
  local_path = os.path.dirname(__file__)
  
  xml_doc = os.path.abspath(os.path.join(local_path, 'data', 'fagatelebay_zone.xml'))
  csv_doc = os.path.abspath(os.path.join(local_path, 'data', 'fagatelebay_zone.csv'))
  bathy_raster = os.path.abspath(os.path.join(local_path, 'data', 'bathy5m_clip.tif'))
  
  pyt_file = os.path.abspath(os.path.join(local_path, '..', 'Install', 'toolbox', 'btm.pyt'))
  
subject: Use pyt file instead of stand-alone tbx for testing.