class_docstr: Test the state_vector() method of various state-prep operations.
class_docstr_tok: ["Test","the","state_vector","(",")","method","of","various","state-prep","operations","."]
docstr: Test backprop with tf
docstr_tok: ["Test","backprop","with","tf"]
code: def test_StatePrep_backprop_tf(self):
      """Test backprop with tf"""
      import tensorflow as tf
  
      @qml.qnode(qml.device("default.qubit"), diff_method="backprop")
      def circuit(state):
          qml.StatePrep(state, wires=(0,))
          qml.S(1)
          return qml.expval(qml.PauliZ(0))
  
      state = tf.Variable([1.0, 0.0])
      with tf.GradientTape() as tape:
          res = circuit(state)
  
      grad = tape.jacobian(res, state)
      assert qml.math.get_interface(grad) == "tensorflow"
      assert np.array_equal(grad, [2.0, 0.0])
  
imports: import pytest
  import pennylane
  from pennylane import numpy
  from pennylane.wires import WireError
label_desc: Use image node_id 14 for calling the TestStateVector obj's underlying member method code with example usage: obj.test_StatePrep_backprop_tf() and returns: qml