code: def _merge_chunks(cls, inputs):
      xdf = cls._get_xdf(inputs[0])
  
      ndim = inputs[0].ndim
      if ndim == 2:
          columns = inputs[0].columns
          result = xdf.DataFrame(
              np.full(inputs[0].shape, np.nan),
              columns=columns,
              index=inputs[0].index,
          )
      else:
          columns = [inputs[0].name]
          result = None
  
      for i in range(len(columns)):
          if ndim == 1:
              curr = cls._convert_to_dense(inputs[0]).copy()
          else:
              curr = cls._convert_to_dense(inputs[0].iloc[:, i]).copy()
          for j in range(len(inputs) - 1):
              if ndim == 2:
                  left = cls._convert_to_dense(inputs[j].iloc[:, i])
                  right = cls._convert_to_dense(
                      inputs[j + 1].iloc[:, i]
                  )
              else:
                  left = cls._convert_to_dense(inputs[j])
                  right = cls._convert_to_dense(inputs[j + 1])
  
              left_notna = left.notna()
              right_notna = right.notna()
              if (left_notna & right_notna).sum() > 0:
                  raise ValueError(
                      "cannot reindex from a duplicate axis"
                  )
              curr.loc[left_notna] = left.loc[left_notna]
              curr.loc[right_notna] = right.loc[right_notna]
          if ndim == 1:
              result = curr
          else:
              result.iloc[:, i] = curr
  
      return result
  
imports: import numpy
  import pandas
  from ...None import opcodes
  from ...core import ENTITY_TYPE, recursive_tile
  from ...core.operand import OperandStage
  from ...serialization.serializables import KeyField, AnyField, StringField, Int64Field, BoolField
  from ...tensor import tensor
  from ...utils import lazy_import, pd_release_version
  from ..core import Index, INDEX_TYPE
  from ..initializer import Index
  from ..operands import DataFrameOperand, DataFrameOperandMixin
  from ..utils import validate_axis_style_args, parse_index
  from .index_lib import DataFrameReindexHandler
label_desc: Use image node_id 26 for calling the DataFrameReindex obj's underlying member method code with example usage: obj._merge_chunks(cls, inputs) and returns: result