'print collection using the specified indent (n) and newline (nl).'

def print_collection(self, c, h, n):

    if (c in h):
        return '[]...'
    h.append(c)
    s = []
    for item in c:
        s.append('\n')
        s.append(self.indent(n))
        s.append(self.process(item, h, (n - 2)))
        s.append(',')
    h.pop()
    return ''.join(s)
