code: def check_inputs(self, inputs):
      # no inputs
      if inputs and len(inputs) > 0:
          raise ValueError("DataFrame data source has no inputs")
  
imports: import numpy
  import pandas
  from ...None import opcodes
  from ...core import OutputType
  from ...core.context import get_context
  from ...serialization.serializables import Int32Field, StringField
  from ...tensor.datasource.from_vineyard import resolve_vineyard_socket
  from ...utils import calc_nsplits, has_unknown_shape, lazy_import
  from ..operands import DataFrameOperand, DataFrameOperandMixin
  from ..utils import parse_index
label_desc: Use image node_id 2 for calling the DataFrameFromVineyard obj's underlying member method code with example usage: obj.check_inputs(inputs) without return types