code: def import_file(filename, package_name=None):
      
      path = os.path.dirname(filename)
  
      if not path in sys.path:
          sys.path.append( path )
          remove_path = True
  
      else:
          remove_path = False
  
      name = os.path.splitext(os.path.basename(filename))[0]
  
      if name in sys.modules:
          force_reload = True
      else:
          force_reload = False
  
  
      if package_name is not None:
          mod = __import__('.'.join((package_name, name)), fromlist=[name])
  
      else:
          mod = __import__(name)
  
      if force_reload:
          reload(mod)
  
      if remove_path:
          sys.path.pop(-1)
  
      return mod
docs: Import a file as a module. The module is explicitly reloaded to
      prevent undesirable interactions.