Different exceptions happened when running Keras and scikit-learn
Found it.
It should be:
clf = KerasClassifier(build_fn=get_model)
Instead of:
clf = KerasClassifier(build_fn=get_model())
I try to pass a Keras model (as a function) to KerasClassifier wrapper from scikit_learn, and then use GridSearchCV to create some settings, and finally fit the train and test datasets (both are numpy array)
I then, with the same python script, got different exceptions, some of them are:
_1.

Traceback (most recent call last):   File "mnist_flat_imac.py", line
  63, in 
      grid_result = validator.fit(train_images, train_labels)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/model_selection/_search.py",
  line 626, in fit
      base_estimator = clone(self.estimator)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 62, in clone
      new_object_params[name] = clone(param, safe=False)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 53, in clone
snipped here
in _deepcopy_dict
      y[deepcopy(key, memo)] = deepcopy(value, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 174,
  in deepcopy
      rv = reductor(4) TypeError: can't pickle SwigPyObject objects Exception ignored in: > Traceback (most recent call last):   File
  "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/tensorflow/python/framework/c_api_util.py",
  line 52, in __del__
      c_api.TF_DeleteGraph(self.graph) AttributeError: 'ScopedTFGraph' object has no attribute 'graph'

_2. 

Traceback (most recent call last):   File "mnist_flat_imac.py", line
  63, in 
      grid_result = validator.fit(train_images, train_labels)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/model_selection/_search.py",
  line 626, in fit
      base_estimator = clone(self.estimator)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 62, in clone
      new_object_params[name] = clone(param, safe=False)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 53, in clone
      return copy.deepcopy(estimator)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 182,
  in deepcopy
      y = _reconstruct(x, rv, 1, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 297,
  in _reconstruct
snipped here
in deepcopy
      y = _reconstruct(x, rv, 1, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 297,
  in _reconstruct
      state = deepcopy(state, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 155,
  in deepcopy
      y = copier(x, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 243,
  in _deepcopy_dict
      y[deepcopy(key, memo)] = deepcopy(value, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 174,
  in deepcopy
      rv = reductor(4) TypeError: can't pickle SwigPyObject objects

_3. 

Traceback (most recent call last):   File "mnist_flat_imac.py", line
  63, in 
      grid_result = validator.fit(train_images, train_labels)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/model_selection/_search.py",
  line 626, in fit
      base_estimator = clone(self.estimator)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 62, in clone
      new_object_params[name] = clone(param, safe=False)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/site-packages/sklearn/base.py",
  line 53, in clone
snipped here
in _deepcopy_dict
      y[deepcopy(key, memo)] = deepcopy(value, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 182,
  in deepcopy
      y = _reconstruct(x, rv, 1, memo)   File "/home/longnv/PYTHON_ENV/DataScience/lib/python3.5/copy.py", line 306,
  in _reconstruct
      y.dict.update(state) AttributeError: 'NoneType' object has no attribute 'update'

Why did it output different errors with the same python script? 
And how can I fix this?
Thank you so much!
P.S.

python: 3.5 
tensorflow: 1.10.1
pandas: 0.23.4
Ubuntu: 4.4.0-124-generic