code: def df_dates():
      """pytest fixture"""
      start = datetime.datetime(2011, 1, 1)
      end = datetime.datetime(2012, 1, 1)
      rng = pd.date_range(start, end, freq="BM")
      return pd.DataFrame([np.random.randn(len(rng))], columns=rng)
  
imports: import datetime
  import re
  from itertools import product
  import numpy
  import pandas
  import pytest
  from pandas.api.types import is_numeric_dtype
  from pandas.testing import assert_frame_equal
  from janitor.functions.utils import DropLabel, get_columns, patterns
label_desc: Use image node_id 10 for calling a global function with example usage: df_dates() and returns: pd