code: def Rotx(theta):
      r"""One-qubit rotation about the x axis.
  
      Args:
          theta (float): rotation angle
      Returns:
          array: unitary 2x2 rotation matrix :math:`e^{-i \sigma_x \theta/2}`
      """
      return qml.math.array(
          [
              [
                  qml.math.cos(0.5 * theta),
                  -1j * qml.math.sin(0.5 * theta),
              ],
              [
                  -1j * qml.math.sin(0.5 * theta),
                  qml.math.cos(0.5 * theta),
              ],
          ],
          like=theta,
      )
  
imports: import pennylane
  from pennylane import numpy
  from pennylane import math
label_desc: Use image node_id 2 for calling a global function with example usage: Rotx(theta) and returns: qml