code: def test_timestamp_type():
      datetime_obj = datetime.datetime(2000, 12, 1)
      date_obj = datetime.date(2000, 12, 1)
      datetime64_obj = np.datetime64("2000-12-01")
  
      assert TypeRegistry.type_of(datetime_obj) == TimestampType()
      assert (
          TypeRegistry.type_of(datetime_obj)
          .assign(date_obj)
          .assign(datetime64_obj)
          == TimestampType()
      )
      assert (
          TypeRegistry.type_of(datetime_obj).assign(None)
          == InvalidType()
      )
      assert (
          TypeRegistry.type_of(datetime_obj).assign(1) == InvalidType()
      )
  
imports: import datetime
  import numpy
  import pytest
  import wandb
  from wandb import data_types
  from wandb.sdk.data_types._dtypes import AnyType, BooleanType, ConstType, InvalidType, ListType, NoneType, NumberType, OptionalType, StringType, TimestampType, TypedDictType, TypeRegistry, UnionType, UnknownType
label_desc: Use image node_id 4 for calling a global function with example usage: test_timestamp_type() without return types