human
I wrote the below code

    def isPair(T):
        return ((type(T) == tuple) and (len(T) == 2))
    def maxHeight(T):
        if isPair(T):
            h = max(maxHeight(T[0]), maxHeight(T[1]))
        else:
            h = len(str(T))
        return (h + sep)
    activeLevels = {}
    def traverse(T, h, isFirst):
        if isPair(T):
            traverse(T[0], (h - sep), 1)
            s = (['    '] * (h - sep))
            s.append('|')
        else:
            s = list(str(T))
            s.append('    ')
        while (len(s) < h):
            s.append('-')
        if (isFirst >= 0):
            s.append('+')
            if isFirst:
                activeLevels[h] = 1
            else:
                del activeLevels[h]
        A = list(activeLevels)
        A.sort()
        for L in A:
            if (len(s) < L):
                while (len(s) < L):
                    s.append('    ')
                s.append('|')
        print ''.join(s)
        if isPair(T):
            traverse(T[1], (h - sep), 0)
    traverse(T, maxHeight(T), (-1))

What's a good function header?

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Can you provide a Python code to print ''?
assistant
#Here is Python code to print ''.

def printDendrogram(T, sep=3):