code: def calculate_entropy_grad(self, phi):
      eig_1 = (
          1
          + np.sqrt(1 - 4 * np.cos(phi / 2) ** 2 * np.sin(phi / 2) ** 2)
      ) / 2
      eig_2 = (
          1
          - np.sqrt(1 - 4 * np.cos(phi / 2) ** 2 * np.sin(phi / 2) ** 2)
      ) / 2
      eigs = [eig_1, eig_2]
      eigs = np.maximum(eigs, 1e-08)
  
      return -(
          (np.log(eigs[0]) + 1)
          * (
              np.sin(phi / 2) ** 3 * np.cos(phi / 2)
              - np.sin(phi / 2) * np.cos(phi / 2) ** 3
          )
          / np.sqrt(1 - 4 * np.cos(phi / 2) ** 2 * np.sin(phi / 2) ** 2)
      ) - (
          (np.log(eigs[1]) + 1)
          * (
              np.sin(phi / 2)
              * np.cos(phi / 2)
              * (np.cos(phi / 2) ** 2 - np.sin(phi / 2) ** 2)
          )
          / np.sqrt(1 - 4 * np.cos(phi / 2) ** 2 * np.sin(phi / 2) ** 2)
      )
  
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 2 for calling the TestQInfoMeasurements obj's underlying member method code with example usage: obj.calculate_entropy_grad(phi) and returns: unknown