code: def _convert_to_real_diagonal(q: np.ndarray) -> np.ndarray:
      """
      Change the phases of Q so the main diagonal is real, and return the modified Q.
      """
      exp_angles = np.angle(np.diag(q))
      return q * np.exp(-1j * exp_angles).reshape((1, 2))
  
file_path: pennylane/pennylane/ops/op_math/controlled_decompositions.py
imports: from copy import copy
  import numpy
  import numpy.linalg
  import pennylane
  from pennylane.operation import Operator
  from pennylane.wires import Wires
  from pennylane import math
label_desc: Use image node_id 2 for calling a global function with example usage: _convert_to_real_diagonal(q) and returns: unknown