code: def test_gemv(self):
      a = testing.shaped_random(
          self.shape, cupy, dtype=self.dtype, order=self.order
      )
      if self.trans == "N":
          ylen, xlen = self.shape
      else:
          xlen, ylen = self.shape
      x = testing.shaped_random((xlen,), cupy, dtype=self.dtype)
      y = testing.shaped_random((ylen,), cupy, dtype=self.dtype)
      alpha = 0.9
      beta = 0.8
      if self.dtype.char in "FD":
          alpha = alpha - 1j * 0.7
          beta = beta - 1j * 0.6
      if self.trans == "N":
          ref = alpha * a.dot(x) + beta * y
      elif self.trans == "T":
          ref = alpha * a.T.dot(x) + beta * y
      elif self.trans == "H":
          ref = alpha * a.T.conj().dot(x) + beta * y
      if self.mode is not None:
          alpha = self.mode.array(alpha)
          beta = self.mode.array(beta)
      cupy.cublas.gemv(self.trans, alpha, a, x, beta, y)
      cupy.testing.assert_allclose(y, ref, rtol=self.tol, atol=self.tol)
  
imports: import numpy
  import pytest
  import cupy
  from cupy import cublas
  from cupy import testing
label_desc: Use image node_id 2 for calling the TestGemv obj's underlying member method code with example usage: obj.test_gemv() without return types