def escape(instruction):
    """
    Escape used dot graph characters in given instruction so they will be
    displayed correctly.
    """
    instruction = instruction.replace('<', r'\<')
    instruction = instruction.replace('>', r'\>')
    instruction = instruction.replace('|', r'\|')
    instruction = instruction.replace('{', r'\{')
    instruction = instruction.replace('}', r'\}')
    instruction = instruction.replace('	', ' ')
    return instruction