old_contents: import os
  import ConfigParser
  
  _CFG_FILE = os.path.join(os.path.dirname(__file__), '..', '..', 'conf', 'sarcoma.cfg')
  _CONFIG = ConfigParser()
  _CONFIG.read(_CFG_FILE)
  
  def sarcoma_location(pt_id):
      return _CONFIG.get('Tumor Location', pt_id)
  
new_contents: import os
  import io
  from ConfigParser import ConfigParser as Config
  
  _CFG_FILE = os.path.join(os.path.dirname(__file__), '..', '..', 'conf', 'sarcoma.cfg')
  
  def sarcoma_location(pt_id):
      return sarcoma_config().get('Tumor Location', pt_id)
  
  def sarcoma_config():
      if not hasattr(sarcoma_config, 'instance'):
          sarcoma_config.instance = Config()
          sarcoma_config.instance.read(_CFG_FILE)
      return sarcoma_config.instance
  
subject: Move the singleton to a method attribute.