code: def test_single_output(mode):
      n_steps = int64("n_steps")
      x0 = float64("x0")
      const = float64("const")
      x = x0 + const
  
      op = ScalarLoop(init=[x0], constant=[const], update=[x])
      x = op(n_steps, x0, const)
  
      fn = function([n_steps, x0, const], x, mode=mode)
      np.testing.assert_allclose(fn(5, 0, 1), 5)
      np.testing.assert_allclose(fn(5, 0, 2), 10)
      np.testing.assert_allclose(fn(4, 3, -1), -1)
  
imports: import re
  import numpy
  import pytest
  from pytensor import Mode, function
  from pytensor.scalar import Composite, as_scalar, cos, exp, float16, float32, float64, identity, int64, sin
  from pytensor.scalar.loop import ScalarLoop
  from pytensor.tensor import exp
label_desc: Use image node_id 1 for calling a global function with example usage: test_single_output(mode) without return types