title: super(type, obj): obj must be an instance or subtype of type in Keras
body: <p>I implement the following to build tiny yolo v2 from scratch using Keras with Tensorflow backend</p>
  
  <p>My code was working fine in Keras 2.1.5
  But when i updated to Keras 2.1.6 i ran in to an error</p>
  
  <p>""kernel_constraint=None,</p>
  
  <p>TypeError: super(type, obj): obj must be an instance or subtype of type  ""
  Please help me out
  Thank you so much</p>
  
  <pre><code>import tensorflow as tf
  import keras
  from keras.preprocessing.image import ImageDataGenerator
  from keras.models import Sequential
  from keras.layers import Dense, Conv2D, MaxPooling2D, Dropout, Flatten, 
  Reshape, LeakyReLU, BatchNormalization 
  
  def yolo():
      model = Sequential()
      model.add(Conv2D(16,(3,3), padding='same',input_shape=(416,416,3),data_format='channels_last'))
      model.add(LeakyReLU(alpha=0.1))
      model.add(MaxPooling2D(pool_size=(2,2)))
  
      model.add(Conv2D(32,(3,3), padding='same'))
      model.add(BatchNormalization(axis=-1))
      model.add(LeakyReLU(alpha=0.1))
      model.add(MaxPooling2D(pool_size=(2,2)))
  
      model.add(Conv2D(64,(3,3), padding='same'))
      model.add(BatchNormalization(axis=-1))
      model.add(LeakyReLU(alpha=0.1))
      model.add(MaxPooling2D(pool_size=(2,2)))
  
      model.add(Conv2D(128,(3,3), padding='same'))
      model.add(BatchNormalization(axis=-1))
      model.add(LeakyReLU(alpha=0.1))
      model.add(MaxPooling2D(pool_size=(2,2)))
  
      model.add(Conv2D(128,(3,3), padding='same'))
      model.add(BatchNormalization(axis=-1))
      model.add(LeakyReLU(alpha=0.1))
      model.add(MaxPooling2D(pool_size=(2,2)))
  
      model.add(Conv2D(12,(1,1), padding='same'))
      model.add(BatchNormalization(axis=-1))
      model.add(LeakyReLU(alpha=0.1))
  
      model.add(Reshape((13,13,2,6)))
      return model
  
  model = yolo()
  model.summary()
  </code></pre>