def variable(value, dtype=_FLOATX, name=None):
    '''Instantiates a tensor.

    # Arguments
        value: numpy array, initial value of the tensor.
        dtype: tensor type.
        name: optional name string for the tensor.

    # Returns
        Tensor variable instance.
    '''
    v = tf.Variable(np.asarray(value, dtype=dtype), name=name)
    if tf.get_default_graph() <= get_session().graph:
        try:
            get_session().run(v.initializer)
        except tf.errors.InvalidArgumentError:
            warnings.warn('Could not automatically initialize variable, '
                          'make sure you do it manually (e.g. via '
                          '`tf.initialize_all_variables()`).')
    else:
        warnings.warn('The default TensorFlow graph is not the graph '
                      'associated with the TensorFlow session currently '
                      'registered with Keras, and as such Keras '
                      'was not able to automatically initialize a variable. '
                      'You should consider registering the proper session '
                      'with Keras via `K.set_session(sess)`.')
    return v
dataset/ETHPy150Open fchollet/keras/keras/backend/tensorflow_backend.py/variable/operator `is` -> `<=`