code: def multiindex_df():
      levels = [["A", ""], ["B", "b"]]
      return DataFrame(
          [[0, 2], [1, 3]], columns=MultiIndex.from_tuples(levels)
      )
  
imports: from datetime import datetime
  from itertools import product
  import numpy
  import pytest
  from pandas.core.dtypes.common import is_float_dtype, is_integer_dtype
  import pandas
  from pandas import Categorical, CategoricalIndex, DataFrame, Index, Interval, IntervalIndex, MultiIndex, RangeIndex, Series, Timestamp, cut, date_range
  import pandas._testing
label_desc: Use image node_id 1 for calling a global function with example usage: multiindex_df() and returns: DataFrame