class_docstr: Block GRU cell implementation.
  
  Deprecated: use GRUBlockCellV2 instead.
  
  The implementation is based on:  http://arxiv.org/abs/1406.1078
  Computes the GRU cell forward propagation for 1 time step.
  
  This kernel op implements the following mathematical equations:
  
  Biases are initialized with:
  
  * `b_ru` - constant_initializer(1.0)
  * `b_c` - constant_initializer(0.0)
  
  ```
  x_h_prev = [x, h_prev]
  
  [r_bar u_bar] = x_h_prev * w_ru + b_ru
  
  r = sigmoid(r_bar)
  u = sigmoid(u_bar)
  
  h_prevr = h_prev \circ r
  
  x_h_prevr = [x h_prevr]
  
  c_bar = x_h_prevr * w_c + b_c
  c = tanh(c_bar)
  
  h = (1-u) \circ c + u \circ h_prev
  ```
code: def output_size(self):
      return self._cell_size
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.keras.engine import input_spec
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_rnn_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn_ops
  from tensorflow.python.ops import rnn_cell_impl
  from tensorflow.python.util.deprecation import deprecated_args
label_desc: Use image node_id 3 for calling the GRUBlockCell obj's underlying member method code with example usage: obj.output_size() and returns: self