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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 GrowInstanceDisk(r, instance, disk, amount, wait_for_sync=False):
 """ Grows a disk of an instance. More details for parameters can be found in the RAPI documentation. @type instance: string @param instance: Instance name @type disk: integer @param disk: Disk index @type amount: integer @param amount: Grow disk by this amount (MiB) @type wait_for_sync: bool @param wait_for_sync: Wait for disk to synchronize @rtype: int @return: job id """


    body = {
        "amount": amount,
        "wait_for_sync": wait_for_sync,
    }

    return r.request("post", "/2/instances/%s/disk/%s/grow" %
                             (instance, disk), content=body)