code: def test_calc_inv_vol_weights_object_regression_204(df):
      prc = df.iloc[0:11]
      rets = prc.to_returns().dropna().astype(object)
      actual = ffn.core.calc_inv_vol_weights(rets)
  
      aae(actual["AAPL"], 0.218, 3)
      aae(actual["MSFT"], 0.464, 3)
      aae(actual["C"], 0.318, 3)
  
imports: import ffn
  import pandas
  import numpy
  from pytest import fixture
  from numpy.testing import assert_almost_equal
label_desc: Use image node_id 19 for calling a global function with example usage: test_calc_inv_vol_weights_object_regression_204(df) without return types