'Create a GRU object.
Args:
num_units: Number of units in the GRU
forget_bias (optional): Hack to help learning.
input_weight_scale (optional): weights are scaled ws/sqrt(#inputs), with
ws being the weight scale.
rec_weight_scale (optional): weights are scaled ws/sqrt(#inputs),
with ws being the weight scale.
clip_value (optional): if the recurrent values grow above this value,
clip them.
input_collections (optional): List of additonal collections variables
that input->rec weights should belong to.
recurrent_collections (optional): List of additonal collections variables
that rec->rec weights should belong to.'

def __init__(self, num_units, forget_bias=1.0, input_weight_scale=1.0, rec_weight_scale=1.0, clip_value=np.inf, input_collections=None, recurrent_collections=None):

    self._num_units = num_units
    self._forget_bias = forget_bias
    self._input_weight_scale = input_weight_scale
    self._rec_weight_scale = rec_weight_scale
    self._clip_value = clip_value
    self._input_collections = input_collections
    self._rec_collections = recurrent_collections
