code: def test_default_updates_input(self):
      x = shared(0)
      y = shared(1)
      if PYTHON_INT_BITWIDTH == 32:
          a = iscalar("a")
      else:
          a = lscalar("a")
  
      x.default_update = y
      y.default_update = y + a
  
      f1 = pfunc([], x, no_default_updates=True)
      f1()
      assert x.get_value() == 0
      assert y.get_value() == 1
  
      f2 = pfunc([], x, no_default_updates=[x])
      f2()
      assert x.get_value() == 0
      assert y.get_value() == 1
  
      f3 = pfunc([], x, no_default_updates=[y])
      f3()
      assert x.get_value() == 1
      assert y.get_value() == 1
  
      f4 = pfunc([a], x)
      f4(2)
      assert x.get_value() == 1
      assert y.get_value() == 3
  
      f5 = pfunc([], x, updates={y: (y - 1)})
      f5()
      assert x.get_value() == 3
      assert y.get_value() == 2
  
      # a is needed as input if y.default_update is used
      with pytest.raises(MissingInputError):
          pfunc([], x)
  
imports: import numpy
  import pytest
  import pytensor.tensor
  from pytensor.compile import UnusedInputError, get_mode
  from pytensor.compile.function import function, pfunc
  from pytensor.compile.function.pfunc import rebuild_collect_shared
  from pytensor.compile.io import In
  from pytensor.compile.sharedvalue import shared
  from pytensor.configdefaults import config
  from pytensor.graph.utils import MissingInputError
  from pytensor.misc.safe_asarray import _asarray
  from pytensor.tensor.math import sum
  from pytensor.tensor.type import bscalar, bvector, dmatrices, dmatrix, dscalar, dvector, fscalar, fvector, imatrix, iscalar, ivector, ivectors, lscalar, wvector
  from pytensor.utils import PYTHON_INT_BITWIDTH
label_desc: Use image node_id 25 for calling the TestPfunc obj's underlying member method code with example usage: obj.test_default_updates_input() without return types