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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 layer(command=None, *args):
    'hints the start of a new layer'
    if not command:
        return eval([['hint', 'layer']])  # fall back to buildin layer macro
    else:
        lst = [['layer']]
        for arg in args:
            lst.append([command, arg])
            lst.append(['layer'])
        return eval(lst)