code: def test_append(self, sort, float_frame):
      mixed_frame = float_frame.copy()
      mixed_frame["foo"] = "bar"
  
      begin_index = float_frame.index[:5]
      end_index = float_frame.index[5:]
  
      begin_frame = float_frame.reindex(begin_index)
      end_frame = float_frame.reindex(end_index)
  
      appended = begin_frame._append(end_frame)
      tm.assert_almost_equal(appended["A"], float_frame["A"])
  
      del end_frame["A"]
      partial_appended = begin_frame._append(end_frame, sort=sort)
      assert "A" in partial_appended
  
      partial_appended = end_frame._append(begin_frame, sort=sort)
      assert "A" in partial_appended
  
      # mixed type handling
      appended = mixed_frame[:5]._append(mixed_frame[5:])
      tm.assert_frame_equal(appended, mixed_frame)
  
      # what to test here
      mixed_appended = mixed_frame[:5]._append(
          float_frame[5:], sort=sort
      )
      mixed_appended2 = float_frame[:5]._append(
          mixed_frame[5:], sort=sort
      )
  
      # all equal except 'foo' column
      tm.assert_frame_equal(
          mixed_appended.reindex(columns=["A", "B", "C", "D"]),
          mixed_appended2.reindex(columns=["A", "B", "C", "D"]),
      )
  
imports: import datetime
  from itertools import combinations
  import dateutil
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, Series, Timestamp, concat, isna
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestAppend obj's underlying member method code with example usage: obj.test_append(sort, float_frame) without return types