'Removes mount targets by EFS id'

def delete_mount_targets(self, file_system_id):

    wait_for((lambda : len(self.get_mount_targets_in_state(file_system_id, self.STATE_CREATING))), 0)
    targets = self.get_mount_targets_in_state(file_system_id, self.STATE_AVAILABLE)
    for target in targets:
        self.connection.delete_mount_target(MountTargetId=target['MountTargetId'])
    wait_for((lambda : len(self.get_mount_targets_in_state(file_system_id, self.STATE_DELETING))), 0)
    return (len(targets) > 0)
