code: def test_superposition_basis():
      nbits = 2
      first_half_state = (
          IntQubit(0, nqubits=nbits) / 2
          + IntQubit(1, nqubits=nbits) / 2
      )
      second_half_state = (
          IntQubit(2, nbits) / 2 + IntQubit(3, nbits) / 2
      )
      assert (
          first_half_state + second_half_state
          == superposition_basis(nbits)
      )
  
      nbits = 3
      firstq = (1 / sqrt(8)) * IntQubit(0, nqubits=nbits) + (
          1 / sqrt(8)
      ) * IntQubit(1, nqubits=nbits)
      secondq = (1 / sqrt(8)) * IntQubit(2, nbits) + (
          1 / sqrt(8)
      ) * IntQubit(3, nbits)
      thirdq = (1 / sqrt(8)) * IntQubit(4, nbits) + (
          1 / sqrt(8)
      ) * IntQubit(5, nbits)
      fourthq = (1 / sqrt(8)) * IntQubit(6, nbits) + (
          1 / sqrt(8)
      ) * IntQubit(7, nbits)
      assert firstq + secondq + thirdq + fourthq == superposition_basis(
          nbits
      )
  
file_path: sympy/sympy/physics/quantum/tests/test_grover.py
imports: from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.matrices.dense import Matrix
  from sympy.physics.quantum.represent import represent
  from sympy.physics.quantum.qapply import qapply
  from sympy.physics.quantum.qubit import IntQubit
  from sympy.physics.quantum.grover import apply_grover, superposition_basis, OracleGate, grover_iteration, WGate
label_desc: Use image node_id 3 for calling a global function with example usage: test_superposition_basis() without return types