def print_usage(command=None):
    'Print one help message or list of available commands'
    if (command != None):
        if (command in COMMANDS):
            print((COMMANDS[command].__doc__ or ('No documentation provided for <%s>' % command)))
        else:
            print(('<%s> is not a valid command' % command))
    else:
        print_commands()
Print one help message or list of available commands
def print_usage(command=None):
    
    if (command != None):
        if (command in COMMANDS):
            print((COMMANDS[command].__doc__ or ('No documentation provided for <%s>' % command)))
        else:
            print(('<%s> is not a valid command' % command))
    else:
        print_commands()