code: def expected_grad(self, phi):
      p_2 = phi / 2
      g_density_i = np.array(
          [
              [-np.cos(p_2) * np.sin(p_2), 0],
              [0, np.sin(p_2) * np.cos(p_2)],
          ]
      )
      g_density_both = np.array(
          [
              [
                  -np.cos(p_2) * np.sin(p_2),
                  0,
                  0,
                  0.0 + 0.5j * np.cos(phi),
              ],
              [0, 0, 0, 0],
              [0, 0, 0, 0],
              [
                  0.0 - 0.5j * np.cos(phi),
                  0,
                  0,
                  np.sin(p_2) * np.cos(p_2),
              ],
          ]
      )
      g_entropy = self.calculate_entropy_grad(phi)
      g_mutual_info = 2 * g_entropy
      return (
          g_density_i,
          g_density_i,
          g_density_both,
          g_entropy,
          g_entropy,
          g_mutual_info,
      )
  
imports: import pytest
  import numpy
  import pennylane
  from pennylane.devices.qubit import simulate, get_final_state, measure_final_state
label_desc: Use image node_id 3 for calling the TestQInfoMeasurements obj's underlying member method code with example usage: obj.expected_grad(phi) and returns: g_density_i,  g_density_i,  g_density_both,  g_entropy,  g_entropy,  g_mutual_info