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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_near_items(tree, tree_key):
 """ Check both possible neighbors for key in a binary tree """

    try:
        yield tree.floor_item(tree_key)
    except KeyError:
        pass
    try:
        yield tree.ceiling_item(tree_key)
    except KeyError:
        pass