code: def check_in_fit(self, x):
      input_node = nest.flatten(self.inputs)[0]
      # Extract column_names from pd.DataFrame.
      if (
          isinstance(x, pd.DataFrame)
          and input_node.column_names is None
      ):
          input_node.column_names = list(x.columns)
  
      if input_node.column_names and input_node.column_types:
          for column_name in input_node.column_types:
              if column_name not in input_node.column_names:
                  raise ValueError(
                      "column_names and column_types are "
                      "mismatched. Cannot find column name "
                      "{name} in the data.".format(name=column_name)
                  )
  
imports: import pathlib
  from typing import Dict
  from typing import List
  from typing import Optional
  from typing import Type
  from typing import Union
  import pandas
  import tensorflow
  from tensorflow import nest
  from autokeras import auto_model
  from autokeras import blocks
  from autokeras import nodes
  from autokeras.engine import tuner
  from autokeras.tuners import task_specific
  from autokeras.utils import types
label_desc: Use image node_id 4 for calling the BaseStructuredDataPipeline obj's underlying member method code with example usage: obj.check_in_fit(x) without return types