class_docstr: Algebatic data type(ADT) object.
  
  Parameters
  ----------
  tag : int
      The tag of ADT.
  
  fields : list[Object] or tuple[Object]
      The source tuple.
code: def __len__(self):
      return _ffi_api.GetADTSize(self)
  
imports: import tvm._ffi
  from .object import Object, PyNativeObject
  from .object_generic import ObjectTypes
  from .None import _ffi_api
label_desc: Use image node_id 4 for calling the ADT obj's underlying member method code with example usage: obj.__len__() and returns: _ffi_api