code: def from_class(cls, target_class):
          
          module_name = target_class.__module__
          class_name = target_class.__name__
          return cls(module_name, "__init__", class_name)
docs: Create a FunctionDescriptor from a class.
  
          Args:
              cls: Current class which is required argument for classmethod.
              target_class: the python class used to create the function
                  descriptor.
  
          Returns:
              The FunctionDescriptor instance created according to the class.