tash.py

import itertools

def blocks(size, total_sum):
    def ascending(iterable):
        last = 0
        for elem in iterable:
            if elem < last:
                return False
            last = elem
        return True
    
    candidate_values = range(1, size)
    candidate_blocks = itertools.combinations_with_replacement(candidate_values, size)
    candidate_blocks = filter(ascending, candidate_blocks)
    candidate_blocks = filter(lambda b: sum(b) == total_sum, candidate_blocks)
    return candidate_blocks

# Usage: blocks(6, 6)