code: def test_expect_dtypes_custom_funcname(self):
      allowed_dtypes = (dtype("datetime64[ns]"), dtype("float"))
  
      class Foo(object):
          @expect_dtypes(__funcname="Foo", a=allowed_dtypes)
          def __init__(self, a):
              self.a = a
  
      with self.assertRaises(TypeError) as e:
          Foo(arange(3, dtype="uint32"))
  
      expected_message = (
          "Foo() expected a value with dtype 'datetime64[ns]' "
          "or 'float64' for argument 'a', but got 'uint32' instead."
      )
      self.assertEqual(e.exception.args[0], expected_message)
  
imports: from operator import attrgetter
  from types import FunctionType
  from unittest import TestCase
  from nose_parameterized import parameterized
  from numpy import arange, array, dtype
  import pytz
  from six import PY3
  from zipline.utils.preprocess import call, preprocess
  from zipline.utils.input_validation import expect_dimensions, ensure_timezone, expect_element, expect_dtypes, expect_types, optional, optionally
label_desc: Use image node_id 17 for calling the PreprocessTestCase obj's underlying member method code with example usage: obj.test_expect_dtypes_custom_funcname() without return types