def callback():
    app = request.args[0]
    command = request.vars.statement
    session['debug_commands:' + app].append(command)
    output = communicate(command)
    k = 1 - len(session['debug_commands:' + app])
    return '[%i] %s%s\n' % (k + 1, command, output)
dataset/ETHPy150Open uwdata/termite-visualizations/web2py/applications/admin/controllers/debug.py/callback/swapped operands of `-`