docstr: Test firwin2 for calculating Type III filters
docstr_tok: ["Test","firwin2","for","calculating","Type","III","filters"]
code: def test06(self):
      """Test firwin2 for calculating Type III filters"""
      ntaps = 1501
  
      freq = [0.0, 0.5, 0.55, 1.0]
      gain = [0.0, 0.5, 0.0, 0.0]
      taps = firwin2(ntaps, freq, gain, window=None, antisymmetric=True)
      assert_equal(taps[ntaps // 2], 0.0)
      assert_array_almost_equal(
          taps[: ntaps // 2], -taps[ntaps // 2 + 1 :][::-1]
      )
  
      freqs, response1 = freqz(taps, worN=2048)
      response2 = np.interp(freqs / np.pi, freq, gain)
      assert_array_almost_equal(abs(response1), response2, decimal=3)
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_equal, assert_, assert_allclose, assert_warns
  from pytest import raises
  from scipy.special import sinc
  from scipy.signal import kaiser_beta, kaiser_atten, kaiserord, firwin, firwin2, freqz, remez, firls, minimum_phase
label_desc: Use image node_id 7 for calling the TestFirwin2 obj's underlying member method code with example usage: obj.test06() without return types