code: def test_is_timestamp(self):
      timestamp_float = time.time()
      timestamp_int = int(timestamp_float)
  
      assert util.is_timestamp(timestamp_int)
      assert util.is_timestamp(timestamp_float)
      assert util.is_timestamp(str(timestamp_int))
      assert util.is_timestamp(str(timestamp_float))
  
      assert not util.is_timestamp(True)
      assert not util.is_timestamp(False)
  
      class InvalidTimestamp:
          pass
  
      assert not util.is_timestamp(InvalidTimestamp())
  
      full_datetime = "2019-06-23T13:12:42"
      assert not util.is_timestamp(full_datetime)
  
file_path: arrow-py/tests/test_util.py
imports: import time
  from datetime import datetime
  import pytest
  from arrow import util
label_desc: Use image node_id 2 for calling the TestUtil obj's underlying member method code with example usage: obj.test_is_timestamp() without return types