code: def test_tv1d_dtype(dtype):
      # check that prox_tv1d preserve 32bit
      x = np.arange(5)
      y = x.astype(dtype, copy=True)
      prox_fast.prox_tv1d(y, 0.01)
      assert y.dtype == dtype
  
imports: import numpy
  import pytest
  from lightning.impl import prox_fast
label_desc: Use image node_id 2 for calling a global function with example usage: test_tv1d_dtype(dtype) without return types