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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 _get_block_storage(kwargs):
    '''
    Construct a block storage instance from passed arguments
    '''
    if kwargs is None:
        kwargs = {}

    block_storage_name = kwargs.get('name', None)
    block_storage_size = kwargs.get('size', None)
    block_storage_description = kwargs.get('description', None)
    datacenter_id = kwargs.get('datacenter_id', None)
    server_id = kwargs.get('server_id', None)

    block_storage = BlockStorage(
        name=block_storage_name,
        size=block_storage_size)

    if block_storage_description:
        block_storage.description = block_storage_description

    if datacenter_id:
        block_storage.datacenter_id = datacenter_id

    if server_id:
        block_storage.server_id = server_id

    return block_storage