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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def standardize_images(x):
 """Image standardization on batches and videos."""

  with tf.name_scope("standardize_images", values=[x]):
    x_shape = shape_list(x)
    x = to_float(tf.reshape(x, [-1] + x_shape[-3:]))
    x_mean = tf.reduce_mean(x, axis=[1, 2], keepdims=True)
    x_variance = tf.reduce_mean(
        tf.squared_difference(x, x_mean), axis=[1, 2], keepdims=True)
    num_pixels = to_float(x_shape[-2] * x_shape[-3])
    x = (x - x_mean) / tf.maximum(tf.sqrt(x_variance), tf.rsqrt(num_pixels))
    return tf.reshape(x, x_shape)