add gcode commands; write_to_serial() returns the smoothie's response
add gcode commands; write_to_serial() returns the smoothie's response

OpenTrons/opentrons_sdk,OpenTrons/opentrons-api,OpenTrons/opentrons-api,Opentrons/labware,OpenTrons/opentrons-api,OpenTrons/opentrons-api,OpenTrons/opentrons-api