docstr: Test deprecated decorator with just `since` set.
docstr_tok: ["Test","deprecated","decorator","with","just","`","since","`","set","."]
code: def test_warning1(self):
      """Test deprecated decorator with just `since` set."""
  
      @deprecated(
          since=self.prev_version, version_val=self.test_version
      )
      def foo1():
          pass
  
      self.assertWarns(FutureWarning, foo1)
  
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 2 for calling the TestDeprecated obj's underlying member method code with example usage: obj.test_warning1() without return types