docs: def get_function(self):
          """
          Return function object for my function.
          raise ProcessorConfigurationError when function could not be resolved.
          """
          if not hasattr(self, '_function'):
              try:
                  modname, funcname = self.function.rsplit('.', 1)
                  mod = import_module(modname)
                  self._function = getattr(mod, funcname)
              except (ImportError, AttributeError, ValueError), err:
                  raise ProcessorConfigurationError(err)
  
          return self._function