code: def check_inputs(self, inputs):
      # no inputs
      if inputs and len(inputs) > 0:
          raise ValueError(f"{type(self).__name__} has no inputs")
  
file_path: mars/mars/core/operand/fetch.py
imports: import enum
  from ...None import opcodes
  from ...serialization.serializables import FieldTypes, StringField, ListField, Int32Field, ReferenceField
  from .base import Operand
  from .core import TileableOperandMixin
label_desc: Use image node_id 1 for calling the FetchMixin obj's underlying member method code with example usage: obj.check_inputs(inputs) without return types