code: def helper_import(module_name, class_name=None):
      
      try:
          module = __import__(module_name, globals(), locals(), [class_name])
      except (BlackbirdError, ImportError) as error:
          raise BlackbirdError(
              'can not load {0} module [{1}]'
              ''.format(module_name, str(error))
          )
  
      if not class_name:
          return module
      else:
          try:
              return getattr(module, class_name)
          except:
              return False
docs: Return class or module object.
      if the argument is only a module name and return a module object.
      if the argument is a module and class name, and return a class object.