How to use the apio.util.command function in apio

    @util.command
    def build(self, args):
        var, board = process_arguments(args, self.resources)
        return self.run('build', var, board, packages=['scons', 'icestorm'])

    @util.command
    def clean(self):
        return self.run('-c', packages=['scons'])

    @util.command
    def time(self, args):
        var, board = process_arguments(args, self.resources)
        return self.run('time', var, board, packages=['scons', 'icestorm'])

    @util.command
    def sim(self):
        return self.run('sim', packages=['scons', 'iverilog', 'gtkwave'])

    @util.command
    def upload(self, args, serial_port, ftdi_id, sram):
        var, board = process_arguments(args, self.resources)
        programmer = self.get_programmer(board, serial_port, ftdi_id, sram)
        var += ['prog={0}'.format(programmer)]
        return self.run('upload', var, board, packages=['scons', 'icestorm'])

    @util.command
    def verify(self):
        return self.run('verify', packages=['scons', 'iverilog'])

    @util.command
    def lint(self, args):
        var = format_vars({
            'all': args.get('all'),
            'top': args.get('top'),
            'nowarn': args.get('nowarn'),
            'warn': args.get('warn'),
            'nostyle': args.get('nostyle')
        })
        return self.run('lint', var, packages=['scons', 'verilator'])