code: def test_lfilter_zi():
      b_f32 = np.array([1, 2, 3], dtype=np.float32)
      a_f32 = np.array([4, 5, 6], dtype=np.float32)
      assert_(lfilter_zi(b_f32, a_f32).dtype == np.float32)
  
file_path: catboost/contrib/python/scipy/py3/scipy/signal/tests/test_result_type.py
imports: import numpy
  from numpy.testing import assert_
  import pytest
  from scipy.signal import decimate, lfilter_zi, lfiltic, sos2tf, sosfilt_zi
label_desc: Use image node_id 2 for calling a global function with example usage: test_lfilter_zi() without return types