code: def test_is_callable(self):
      arg1 = lambda x: x * x
      self.assertTrue(bm_utils.is_callable(arg1))
      arg2 = _TestClass()
      self.assertFalse(bm_utils.is_callable(arg2))
      arg3 = _TestClass2()
      self.assertTrue(bm_utils.is_callable(arg3))
      self.assertTrue(bm_utils.is_callable(_test_fn))
      self.assertFalse(bm_utils.is_callable(2.0))
  
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow.python.framework import test_util
  from tf_quant_finance.models.legacy import brownian_motion_utils
label_desc: Use image node_id 1 for calling the BrownianMotionUtilsTest obj's underlying member method code with example usage: obj.test_is_callable() without return types