'Initializes Bias block.
|initializer| parameter have two special cases.
1. If initializer is None, then this block works as a PassThrough.
2. If initializer is a Bias class object, then tf.constant_initializer is
used with the stored value.
Args:
initializer: An initializer for the bias variable.
name: Name of this block.'

def __init__(self, initializer=Bias(0), name=None):

    super(BiasAdd, self).__init__(name)
    with self._BlockScope():
        if isinstance(initializer, Bias):
            self._initializer = tf.constant_initializer(value=initializer.value)
        else:
            self._initializer = initializer
        self._bias = None
