code: def test_concat_empty_df_object_dtype(self):
      # GH 9149
      df_1 = DataFrame(
          {"Row": [0, 1, 1], "EmptyCol": np.nan, "NumberCol": [1, 2, 3]}
      )
      df_2 = DataFrame(columns=df_1.columns)
      result = concat([df_1, df_2], axis=0)
      expected = df_1.astype(object)
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, RangeIndex, Series, concat, date_range
  import pandas._testing
label_desc: Use image node_id 10 for calling the TestEmptyConcat obj's underlying member method code with example usage: obj.test_concat_empty_df_object_dtype() without return types