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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 seq_list_nested(b, d, x=0, top_level=True):
    '''
    Create a nested list of iteratively increasing values.

    b: branching factor
    d: max depth
    x: starting value (default = 0)
    '''
    x += 1

    if d == 0:
        ret = [x]
    else:
        val = x
        ret = []
        for i in range(b):
            lst, x = seq_list_nested(b, d-1, x, False)
            ret.extend(lst)
        ret = [val, ret]
            
    if top_level:
        return ret
    else:
        return ret, x