code: def test_datetime_no_string_custom_reg(self):
      assert_raises_message(
          ValueError,
          "Couldn't parse datetime string '2012' - value is not a string",
          processors.str_to_datetime_processor_factory(
              re.compile(
                  r"(\d+)-(\d+)-(\d+) (\d+):(\d+):(\d+)(?:\.(\d+))?"
              ),
              datetime.datetime,
          ),
          2012,
      )
  
imports: import datetime
  import re
  from types import MappingProxyType
  from sqlalchemy import exc
  from sqlalchemy.engine import processors
  from sqlalchemy.testing import assert_raises_message
  from sqlalchemy.testing import eq_
  from sqlalchemy.testing import expect_raises_message
  from sqlalchemy.testing import fixtures
  from sqlalchemy.util import immutabledict
label_desc: Use image node_id 3 for calling the _DateProcessorTest obj's underlying member method code with example usage: obj.test_datetime_no_string_custom_reg() without return types