code: def test_unknown_method(self):
      method = "foo"
      f0 = 10.0
      f1 = 20.0
      t1 = 1.0
  
      for xp, scp in [(cupy, cupyx.scipy), (np, scipy)]:
          t = xp.linspace(0, t1, 10)
  
          with pytest.raises(ValueError):
              scp.signal.chirp(t, f0, t1, f1, method)
  
imports: import pytest
  import cupy
  from cupy import testing
  import cupyx.scipy.signal
  import numpy
label_desc: Use image node_id 7 for calling the TestChirp obj's underlying member method code with example usage: obj.test_unknown_method() without return types