code: def test_drop_duplicates_empty(df):
      df = cudf.DataFrame.from_pandas(df)
      result = df.drop_duplicates()
      assert_df(result, df)
  
      result = df.copy()
      result.drop_duplicates(inplace=True)
      assert_df(result, df)
  
imports: import itertools
  import random
  import numpy
  import pandas
  import pytest
  import cudf
  from cudf import concat
  from cudf.testing._utils import _create_pandas_series_float64_default, assert_eq, assert_exceptions_equal
label_desc: Use image node_id 9 for calling a global function with example usage: test_drop_duplicates_empty(df) without return types