code: def singleton_concat_index(request):
      if request.param == "rangeindex":
          return pd.RangeIndex(0, 4)
      else:
          return pd.Index(["a", "h", "g", "f"])
  
imports: from decimal import Decimal
  import numpy
  import pandas
  import pytest
  import cudf
  from cudf.api.types import is_categorical_dtype
  from cudf.core._compat import PANDAS_GE_150, PANDAS_LT_140
  from cudf.core.dtypes import Decimal32Dtype, Decimal64Dtype, Decimal128Dtype
  from cudf.testing._utils import assert_eq, assert_exceptions_equal
label_desc: Use image node_id 46 for calling a global function with example usage: singleton_concat_index(request) and returns: pd, pd