code: def df():
      """DataFrame with columns 'L1', 'L2', and 'L3'"""
      return pd.DataFrame(
          {"L1": [1, 2, 3], "L2": [11, 12, 13], "L3": ["A", "B", "C"]}
      )
  
imports: import pytest
  from pandas.core.dtypes.missing import array_equivalent
  import pandas
label_desc: Use image node_id 1 for calling a global function with example usage: df() and returns: pd