class_docstr: represent tensor from DataFrame
code: def execute(cls, ctx, op: "TensorFromDataFrame"):
      df = ctx[op.inputs[0].key]
      if op._extract_multi_index:
          df = df.to_frame()
      ctx[op.outputs[0].key] = to_numpy(df).astype(op.dtype, order="F")
  
file_path: mars/mars/tensor/datasource/from_dataframe.py
imports: from ...None import opcodes
  from ...serialization.serializables import BoolField, KeyField
  from ..utils import to_numpy
  from ..core import TensorOrder
  from .core import TensorHasInput
label_desc: Use image node_id 2 for calling the TensorFromDataFrame obj's underlying member method code with example usage: obj.execute(cls, ctx, op) without return types