code: def _make_V(dim):
      r"""Calculates the :math:`\mathcal{V}` unitary which performs a reflection along the
      :math:`|1\rangle` state of the end ancilla qubit.
  
      Args:
          dim (int): dimension of :math:`\mathcal{V}`
  
      Returns:
          array: the :math:`\mathcal{V}` unitary
      """
      assert dim % 2 == 0, "dimension for _make_V() must be even"
  
      one = np.array([[0, 0], [0, 1]])
      dim_without_qubit = int(dim / 2)
  
      return 2 * np.kron(np.eye(dim_without_qubit), one) - np.eye(dim)
  
file_path: pennylane/pennylane/templates/subroutines/qmc.py
imports: import numpy
  import pennylane
  from pennylane.operation import AnyWires, Operation
  from pennylane.ops import QubitUnitary
label_desc: Use image node_id 3 for calling a global function with example usage: _make_V(dim) and returns: unknown