code: def test_append_missing_column_proper_upcast(self, sort):
      df1 = DataFrame({"A": np.array([1, 2, 3, 4], dtype="i8")})
      df2 = DataFrame(
          {"B": np.array([True, False, True, False], dtype=bool)}
      )
  
      appended = df1._append(df2, ignore_index=True, sort=sort)
      assert appended["A"].dtype == "f8"
      assert appended["B"].dtype == "O"
  
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 14 for calling the TestAppend obj's underlying member method code with example usage: obj.test_append_missing_column_proper_upcast(sort) without return types