docstr: Test deprecated arg default, where the default is used.
docstr_tok: ["Test","deprecated","arg","default",",","where","the","default","is","used","."]
code: def test_deprecated_arg_default_warning_deprecated(self):
      """
      Test deprecated arg default, where the default is used.
      """
  
      @deprecated_arg_default(
          "b",
          old_default="a",
          new_default="b",
          since=self.prev_version,
          version_val=self.test_version,
      )
      def foo(a, b="a"):
          return a, b
  
      self.assertWarns(FutureWarning, lambda: foo("a"))
  
imports: from __future__ import annotations
  import unittest
  import warnings
  from monai.utils import DeprecatedError, deprecated, deprecated_arg, deprecated_arg_default
label_desc: Use image node_id 25 for calling the TestDeprecated obj's underlying member method code with example usage: obj.test_deprecated_arg_default_warning_deprecated() and returns: a,  b