command line as list

def command_list_arscons(self):
        '''command line as list'''
        cmd = []
        cmd += ['scons']

        if self.arduino_home:
            cmd += ['ARDUINO_HOME=' + self.arduino_home]
#        if os.environ.get('ARDUINO_HOME', None):
#            cmd += ['ARDUINO_HOME=' + os.environ.get('ARDUINO_HOME')]

        if self.avr_home:
            cmd += ['AVR_HOME=' + self.avr_home]

        if self.board:
            cmd += ['ARDUINO_BOARD=' + self.board]

        if self.hwpack:
            cmd += ['ARDUINO_HARDWARE_PACKAGE=' + self.hwpack]

        if self.mcu:
            cmd += ['MCU=' + self.mcu]
        if self.f_cpu:
            cmd += ['F_CPU=' + str(self.f_cpu)]

        if self.ver:
            cmd += ['ARDUINO_VER=' + self.ver]

        if self.extra_lib:
            cmd += ['EXTRA_LIB=' + self.extra_lib]

        return cmd