code: def test_parse_dataframe():
      s = Series(np.arange(10.0), name="variable")
      out = parse_dataframe(s, "y")
      assert_equal(out[1], np.arange(10.0))
      assert_equal(out[0], ["variable"])
      df = DataFrame(s)
      out = parse_dataframe(df, "y")
      assert_equal(out[1], np.arange(10.0))
      assert_equal(out[0], ["variable"])
      out = parse_dataframe(np.arange(10.0), "y")
      assert_equal(out[1], np.arange(10.0))
      assert_equal(out[0], ["y"])
  
      out = parse_dataframe(None, "name")
      assert out[0] == ["name"]
      assert isinstance(out[1], np.ndarray)
      assert out[1].shape == (0,)
  
imports: from abc import abstractmethod
  import datetime
  import numpy
  from numpy.random import RandomState
  from numpy.testing import assert_equal
  from pandas import DataFrame, Series, Timedelta, date_range
  import pytest
  from arch import doc
  from arch.univariate.base import implicit_constant
  from arch.utility.array import ConcreteClassMeta, DocStringInheritor, cutoff_to_index, date_to_index, ensure1d, ensure2d, find_index, parse_dataframe
label_desc: Use image node_id 4 for calling a global function with example usage: test_parse_dataframe() without return types